Length converter
Metric to imperial. Any distance, instantly.
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Conversions
Percentage calculator
Calculate a percentage, discount or increase.
Bill splitter
Split the total fairly, including the tip.
Date difference
Count the days between two dates.
Weight converter
Grams, kilograms, ounces and pounds.
Word & character counter
Words, characters and reading time.
Temperature converter
Celsius, Fahrenheit and Kelvin, in sync.
Recipe scaler
Adjust ingredient quantities for any number of servings.
Knitting shaping row planner
Distribute one-stitch increases or decreases across a row schedule.
Crochet circle round counts
Build a round-by-round stitch-count reference for constant increases.
Quilt block layout planner
Preview a square-block quilt and calculate finished and cut dimensions.
Half-square triangle cut planner
Plan two-at-a-time HST starting squares with explicit trimming allowance.
Patchwork strip cutting yield
Estimate fabric length and spare pieces from repeated rectangular strip cuts.
Cross-stitch fabric size
Preview the stitched rectangle and fabric margins from count and stitch dimensions.
Embroidery thread budget
Estimate skein quantity from measured stitch use and working strands.
Weaving sett and reed planner
Compare target warp ends with a fixed reed denting arrangement.
Weaving warp length budget
Budget warp per end and total yarn for repeated woven pieces.
Macramé cord cutting budget
Turn a measured knot multiplier into cut lengths and spool counts.
Picture frame mat layout
Preview an artwork opening with centred or bottom-weighted borders.
Resin casting material budget
Estimate mixed volume and component masses from supplied product data.
Square-foot garden grid
Create a labelled planting allocation grid from your chosen cell density.
Garden sowing date worksheet
Turn crop offsets into dated sowing and transplant plans.
Succession planting schedule
Plan repeated sowings and expected harvest dates on a calendar.
Seed germination batch log
Compare observed germination rates across your seed batches.
Drip irrigation zone budget
Group whole drip lines within a supplied flow capacity.
Sprinkler catch-can analysis
Calculate catch-depth uniformity and application rate from your measurements.
Compost carbon–nitrogen mass balance
Combine supplied dry-mass carbon and nitrogen compositions.
Fertiliser nutrient mass budget
Sum declared N–P₂O₅–K₂O masses across listed products.
Recipe batch scaling table
Scale a complete ingredient table while retaining each stated unit.
Ingredient composition table
Express each ingredient as a percentage of the total mix mass.
Pizza party portion planner
Combine group appetites and round the slice budget up to whole pizzas.
Desired dough water temperature
Apply the empirical temperature-factor worksheet with your mixer friction value.
Coffee extraction comparison log
Compare apparent extraction yield from dose, beverage mass and measured TDS.
Multi-stage starter build budget
Track flour, water and carried starter mass across explicit feeding stages.
Meal prep container allocation
Allocate whole portions into full containers and a remainder container.
Dehydration mass balance
Estimate final mass from starting and target wet-basis water percentages.
Shelf carcass panel cut list
List rectangular panels for a simple between-side shelf cabinet.
Paver grid and edge-cut plan
Preview a straight paver grid and export every full or edge-cut position.
Window blind measurement worksheet
Compare three opening measurements and apply a supplied deduction.
Moving box weight allocation
Group listed item units within your chosen box mass budget.
Party seating allocation
Keep parties together while filling tables with a simple transparent heuristic.
Volunteer role rotation
Create repeatable round-by-round role assignments from your own participant list.
Round-robin fixture maker
Generate every pair once, with automatic byes for odd participant counts.
Knockout bracket worksheet
Build a single-elimination match path with first-round byes.
Packing weight manifest
Sum item quantities and compare the contents mass of each named bag.
Household chore rotation
Create a weekly task worksheet with a predictable person rotation.
Parallel task schedule planner
Schedule independent jobs across equal lanes and visualise elapsed time.
Deadline status board
Sort a dated task table by days remaining relative to your reference date.
Text concordance / KWIC
Inspect every literal keyword occurrence with surrounding context.
N-gram frequency analyser
Find repeated word phrases or character sequences in local text.
Lexical text similarity
Compare token overlap and frequency with three transparent scores.
Fuzzy string list matcher
Rank candidate names or labels by editable character distance.
Character frequency table
Count exact characters and spot repeated whitespace or unusual code points.
Literal text redactor
Replace a supplied list of private terms with a consistent marker.
Unicode text normaliser
Compare canonical or compatibility Unicode forms and export normalised text.
Unicode escape converter
Encode text as Unicode escapes or decode them without executing code.
Email address list cleaner
Trim and deduplicate a simple address list while reporting syntax problems.
ISBN checksum and converter
Check ISBN-10/13 digits and convert compatible book number formats.
Barcode check digit calculator
Generate or check EAN-8, UPC-A and EAN-13 arithmetic checksums.
Luhn checksum calculator
Generate or verify a modulo-10 check digit on a numeric string.
CSV dataset diff
Compare two keyed datasets and export exact record and cell changes.
CSV rule validator
Check required fields and declared column types without uploading records.
CSV calculated column
Apply a safe mathematical expression to a numeric column and append the result.
CSV rank and percentile
Rank rows with clear tie rules and retain the original record order.
Grouped CSV rolling window
Add trailing moving summaries while keeping groups and input order intact.
Grouped CSV fill down
Carry previous non-empty values forward separately within each group.
CSV value recoder
Apply an explicit whole-cell value map without substring replacements.
CSV identifier padding
Pad textual IDs to a fixed minimum width without losing leading zeros.
CSV date reformatter
Reformat a column of strict ISO dates without locale guessing.
CSV numeric string cleaner
Remove declared grouping and currency wrappers while preserving decimal digits.
CSV split cells into rows
Expand list-valued cells into separate records using a literal separator.
CSV group and concatenate
Collect text values into one ordered list per group.
CSV side-by-side combiner
Combine tables by row position with strict or blank-padded alignment.
CSV missingness map
Visualise empty-cell patterns and compare completeness across columns.
CSV record card maker
Turn table rows into printable cards with a safe local HTML preview.
CSV to SQL INSERT statements
Build quoted INSERT statements while retaining text identifiers and values.
CSV file splitter
Split a table into a ZIP of grouped or fixed-size CSV files.
CSV points to GeoJSON
Build a GeoJSON FeatureCollection from latitude and longitude columns.
JSON Pointer query
Select a nested value using an exact JSON Pointer, preserving large numeric tokens.
JSON Merge Patch
Apply an object merge patch or replace a JSON target with a new value.
JSON Patch applier
Apply a checked sequence of add, remove, replace, move, copy and test operations.
Structural JSON diff
Compare nested JSON values by keys and array positions without rounding large identifiers.
JSON flatten & rebuild
Create a reversible typed JSON Pointer manifest and rebuild the original structure.
JSON observed-shape summary
Inspect path types and occurrence counts across a nested JSON document.
JSON array & NDJSON converter
Convert between an array and one JSON value per line while preserving numeric tokens.
NDJSON record filter
Filter private line-delimited records using a JSON Pointer and typed equality.
GeoJSON structure inspector
Inspect geometry counts, position ranges and common structural errors locally.
GeoJSON points to CSV
Extract Point and MultiPoint coordinates into an ordinary downloadable table.
Rectangle section properties
Find centroidal area moments and elastic section moduli for a rectangular section.
Elastic bending stress
Calculate outer-fibre normal stress from bending moment and elastic section modulus.
Beam deflection curves
Plot deflection along a simply supported or cantilever beam for common loading cases.
Euler column buckling
Estimate ideal elastic critical load from effective length and section inertia.
Circular shaft torsion
Calculate elastic shear stress and twist for solid or hollow circular shafts.
Elastic axial extension
Calculate axial stress, strain and length change of a uniform elastic member.
Belt pulley speeds
Compare pulley RPM and belt speed with a supplied slip allowance.
Open belt pitch length
Find the geometric belt length and wrap angles between two pulleys.
Compound gear train table
Track stage ratios, speed and rotation direction through a compound external gear train.
Spur gear pitch geometry
Translate module and tooth count into common involute gear reference diameters.
Lead screw motion & torque
Relate screw lead, rotational speed, axial force and efficiency.
Hydraulic cylinder force & speed
Compare extension and retraction force, speed and stroke time.
Hydraulic fluid & shaft power
Convert pressure difference and volume flow into fluid power and input power.
Pump affinity scaling
Scale flow, head and power with rotational speed under ideal similarity assumptions.
Pipe mean flow velocity
Find mean liquid speed from circular bore diameter and volume flow.
Pipe Reynolds number
Calculate Reynolds number with explicit density and dynamic viscosity.
Darcy pipe friction loss
Estimate straight-pipe pressure loss using a flow-regime-aware Darcy factor.
Pipe fitting minor-loss table
Combine fitting loss coefficients on one velocity basis.
Liquid orifice discharge
Estimate discharge from head, circular opening size and a supplied coefficient.
Venturi liquid flow estimate
Calculate volume flow from upstream/throat diameters and differential pressure.
Gravity tank drain curve
Plot liquid head and outflow as a constant-area tank drains.
Manning open-channel flow
Estimate uniform flow in a rectangular or trapezoidal channel.
Open-channel Froude number
Compare flow speed with the shallow-water gravity-wave scale.
Bernoulli mechanical head
Separate pressure, velocity and elevation contributions to fluid head.
Hydrostatic force on a vertical rectangle
Find the resultant gauge force and centre-of-pressure depth.
Aerodynamic drag & power
Calculate drag and steady power from a supplied drag coefficient and area.
Stokes settling velocity
Estimate a small sphere’s settling speed and inspect the resulting Reynolds number.
Ideal rocket delta-v
Relate mass ratio and specific impulse to ideal velocity change.
Ideal circular orbit
Calculate circular speed, period and local escape speed around a supplied central mass.
Coplanar Hohmann transfer
Compare ideal tangential impulses and coast time between two circular orbits.
Free-space radio path loss
Calculate ideal geometric radio loss from frequency and separation.
Fresnel zone clearance
Find a radio Fresnel-zone radius at a point along a path.
Conductor skin depth
Estimate field decay depth in a uniform good conductor.
Wire resistance & temperature
Calculate conductor resistance and apply a supplied linear temperature coefficient.
Battery energy runtime
Estimate constant-load runtime after supplied usable-depth and efficiency factors.
Battery series/parallel arithmetic
Compare nominal pack voltage, capacity, energy and cell current sharing.
Solar array energy budget
Estimate energy from array rating, equivalent peak-sun hours and supplied derating.
Layered wall heat flow
Combine material and surface-film resistances and inspect interface temperatures.
Greybody radiative heat exchange
Compare emitted power and net exchange with a large surrounding environment.
Newton cooling & heating curve
Estimate time to a target temperature using a supplied first-order rate constant.
Convex hull builder
Find and plot the outer boundary of a point cloud.
Closest pair in a point cloud
Find the nearest two points and show their distance on a plot.
Polygon centroid calculator
Locate the uniform-area centre of a simple polygon and plot it.
Point-in-polygon checker
Test whether a point lies inside, outside or on the edge of a polygon.
Line segment intersection
Find a crossing point or collinear overlap between two finite segments.
Circle intersection points
Find the intersection coordinates of two circles and view their geometry.
Infinite line & circle intersections
Find where the line through two points crosses a circle.
Triangle centres from coordinates
Plot the centroid, incentre, circumcentre, orthocentre and nine-point centre.
2D point transformation
Scale, rotate and translate a point set with a comparison plot and CSV export.
Bézier curve sampler
Turn control points into an exportable curve and inspect the control polygon.
Complex number arithmetic
Add, subtract, multiply or divide complex numbers and inspect polar form.
Nth roots of a complex number
List and plot all distinct nth roots of a complex value.
2D polar & Cartesian converter
Convert planar coordinates while keeping angle and zero-radius conventions explicit.
Triangle barycentric coordinates
Express a point as weights of three triangle vertices and check containment.
Point-to-plane distance
Find signed distance and the closest point on a 3D plane.
Plane through three 3D points
Find a unit-normal plane equation from three non-collinear coordinates.
3D line & plane intersection
Intersect an infinite directed line with a plane or identify parallel cases.
Intersection of two planes
Find a point and unit direction for the line where two 3D planes meet.
3D Euler rotation workspace
Apply an explicit X–Y–Z rotation order and inspect the resulting matrix.
Quaternion vector rotation
Normalise a Hamilton quaternion and use it to rotate a 3D vector.
Polynomial evaluator
Evaluate a coefficient list and its derivative using Horner arithmetic.
Polynomial arithmetic
Add, subtract or multiply polynomial coefficient lists and export the resulting coefficients.
Polynomial long division
Divide two polynomial coefficient lists and inspect quotient and remainder.
Adaptive numerical integration
Estimate a definite integral with an evaluation count and error estimate.
Numerical derivative workspace
Estimate first and second derivatives and compare sensitivity to the chosen step.
Bracketed root finder
Find one root in a sign-changing interval and inspect the final residual.
Function value table
Sample an expression at evenly spaced X positions and export the full table.
Finite difference table
Build successive forward differences from equally spaced observations.
Polynomial interpolation workspace
Interpolate up to 20 points and export a sampled polynomial curve.
Natural cubic spline workspace
Interpolate an ordered point set with natural endpoint conditions and export samples.
Row reduction, rank & nullspace
Reduce a small matrix and inspect pivot columns, numerical rank and nullspace basis.
2 × 2 eigenvalue calculator
Find real or complex-conjugate eigenvalues of a real 2 × 2 matrix.
Cholesky decomposition
Factor a small symmetric positive-definite matrix as L times its transpose.
Pivoted LU decomposition
Inspect lower and upper triangular factors and the row permutation.
QR decomposition
Factor a small matrix into an orthonormal basis and upper-triangular coefficients.
Polynomial least-squares fit
Fit a low-degree curve to point data and inspect fitted values and residuals.
Iterative linear-system solver
Trace Jacobi or Gauss–Seidel iterations and inspect residual convergence.
Chinese remainder solver
Solve compatible integer congruences, including non-coprime moduli.
Modular multiplicative inverse
Find an exact integer inverse and verify the modular product.
Continued fractions & convergents
Inspect rational convergents of a supplied decimal number.
CSV heatmap builder
Explore a numeric matrix as a labelled heatmap, with readable values and SVG export.
Box plot builder
Compare grouped distributions, medians, spread and outliers from your own CSV.
Weighted decision matrix
Compare options using your own criteria, directions and weights, with an exportable ranking.
Venn diagram builder
Compare two or three lists, see exact overlaps and export the diagram and memberships.
CSV chart builder
Turn a local CSV into a bar, line or scatter chart with editable columns and SVG export.
WAV waveform & trimmer
Inspect a waveform, choose a region, preview it and download a trimmed WAV locally.
ZIP archive inspector
Browse a ZIP, search its files and extract individual entries without uploading the archive.
Image comparison slider
Slide between two images or inspect a highlighted pixel-difference map.
Image colour palette extractor
Extract a sampled palette, inspect colour contrast and download reusable swatches.
Interactive function plotter
Graph up to three expressions, zoom the viewport and inspect values along the X axis.
Project timeline & Gantt chart
Turn dated tasks into an editable timeline with progress bars and SVG export.
Room layout planner
Arrange furniture rectangles on a measured room plan, with snapping, keyboard controls and SVG export.
Interactive pendulum simulation
Change a pendulum’s length, gravity and damping, then watch its motion and angle trace.
Loaded voltage divider
Calculate a resistor divider with an optional load across its lower resistor.
Two-branch current divider
Split a supplied total current between two ideal parallel resistors.
LED series resistor calculator
Estimate the ideal resistor and dissipation for a low-voltage DC LED string.
First-order RC filter
Find the ideal cutoff, gain and phase of an unloaded RC low-pass or high-pass filter.
RL current rise calculator
Explore an ideal series RL step response and stored magnetic energy.
LC resonance calculator
Calculate an ideal LC resonant frequency and the series-RLC quality factor.
Capacitive & inductive reactance
Find ideal reactance magnitudes and signed imaginary impedance at a frequency.
Series RLC impedance
Calculate impedance, RMS current, phase and real power for an ideal series RLC circuit.
Waveform RMS & peak
Compare peak, peak-to-peak and RMS for ideal symmetric periodic waveforms.
Ideal transformer ratios
Relate winding turns, RMS voltages, currents and reflected resistance.
Ideal op-amp gain
Compare ideal inverting and non-inverting closed-loop amplifier results.
555 astable timer calculator
Estimate standard 555 timing, frequency and high-state duty cycle.
Capacitor charge sharing
Calculate the ideal final voltage when two charged capacitors are connected in parallel.
Resistor colour code reader
Decode four- or five-band resistor values and tolerance limits.
Resistor tolerance checker
Compare a set of measured resistances against a nominal value and tolerance.
Molality calculator
Calculate solute moles per kilogram of solvent, keeping solvent and solution mass separate.
Ideal osmotic pressure
Estimate dilute-solution osmotic pressure from concentration and a particle factor.
Serial dilution planner
Build a concentration table for equal-volume repeated dilution steps.
Solution concentration by blending
Mix two solutions of the same solute using mass percentages.
pH, pOH & concentration
Relate pH, pOH and idealised hydronium/hydroxide concentrations using a stated pKw.
Weak acid buffer pH
Explore the Henderson–Hasselbalch model with a stated conjugate pair.
Boiling & freezing point shifts
Estimate ideal boiling-point elevation and freezing-point depression from molality.
Arrhenius rate ratio
Compare rate constants at two absolute temperatures using an activation energy.
Ideal gas density calculator
Calculate mass density from absolute pressure, temperature and molar mass.
Reaction percentage yield
Compare actual product yield with a supplied theoretical yield.
3D vector calculator
Calculate lengths, dot and cross products, angle and vector projection.
Small matrix calculator
Add, multiply, transpose, invert or find a determinant for matrices up to 6 × 6.
Triangle from sides & angles
Solve a plane triangle from two sides and their included angle, or one side and two angles.
Circle through three points
Find the circumcentre, radius and equation of the circle through three plane points.
Cartesian & spherical coordinates
Translate 3D Cartesian coordinates and radius/azimuth/polar-angle coordinates.
Date range generator
Create a dated list at fixed day intervals, with weekday or weekend filtering.
Recurring date planner
Generate anchored weekly, monthly or yearly dates with a clear month-end policy.
Nth weekday of a month
Find the first to fifth, or last, chosen weekday in a month.
Add or subtract working days
Move a date using your chosen weekdays and excluded-date list.
Work calendar hours
Summarise eligible dates and assumed working hours by month.
Fiscal year & quarter
Find the year and quarter boundaries for a fiscal year starting in a chosen month.
Date range overlap
Find shared days, combined coverage and the gap between two inclusive date ranges.
Merge date ranges
Combine overlapping inclusive date ranges without double-counting covered days.
Shift a list of dates
Move dates by days or calendar months while preserving their input order.
Date format converter
Translate explicitly ordered numeric dates into unambiguous formats.
Add duration to a clock time
Add or subtract seconds and keep track of midnight crossings.
Merge clock-time intervals
Calculate distinct occupied time from overlapping same-day intervals.
Elapsed time between dated instants
Compare two ISO date-times with explicit UTC offsets.
Annual date planner
List the next occurrence of recurring month/day dates after a chosen reference date.
ISO week date to calendar date
Turn a week-year, ISO week and weekday into a Gregorian calendar date.
Julian date converter
Translate UTC calendar date-times and astronomical Julian dates.
Excel date serial converter
Translate date-times and spreadsheet serials while exposing the 1900 leap-day anomaly.
ISO day-time duration converter
Convert a fixed ISO-style day/time duration to seconds and back.
Calendar event file creator
Create a downloadable .ics file for one all-day or UTC-timed event.
12-hour & 24-hour time converter
Translate explicitly written AM/PM times and 24-hour clock times.
Curtain fabric planner
Estimate joined fabric widths, repeat-matched drops and total fabric length.
Fabric shrinkage calculator
Measure shrinkage in each direction and allow for it before cutting.
Knitting & crochet gauge planner
Turn a measured swatch into stitch and row counts, including repeat multiples.
Quilt binding calculator
Plan straight-grain binding strips and fabric yardage from a quilt perimeter.
Bias binding fabric area
Estimate the fabric area behind a chosen length and cut width of bias strip.
Yarn quantity substitution
Match a pattern’s total yarn length to a replacement skein size.
Bead string length planner
Fit whole beads and spacers into a target necklace or bracelet length.
Circle skirt dimensions
Calculate waist and hem radii for full, half and quarter circle skirt sectors.
Evenly spaced objects
Lay out identical objects with equal edge gaps or fixed end clearances.
Board feet calculator
Calculate sawn-lumber volume and a price estimate from board dimensions.
Picture hanging layout
Position a centred picture and one or two aligned hanging points.
Equal mitre angle calculator
Find matching mitre cuts for a flat corner or a regular polygon frame.
Sourdough starter feeding planner
Build a target starter amount with a stated seed:flour:water feeding ratio.
Dough ball batch planner
Plan a batch weight, handling allowance and ingredient quantities for dough portions.
Brine percentage calculator
Distinguish salt as a percentage of water from salt as a percentage of final brine.
Coffee brew ratio calculator
Calculate coffee or brew-water input using a chosen mass ratio.
Chocolate cocoa percentage blend
Mix two labelled cocoa percentages to reach a target batch composition.
Fat content substitution
Match the fat mass of one ingredient using another ingredient’s labelled fat percentage.
Loaf pan dough loading
Estimate a dough batch from internal pan volume and your chosen loading rate.
Water mixing temperature
Estimate an equilibrium temperature or hot/cold masses for a target temperature.
Annulus calculator
Find the area, ring width and boundary lengths of a circular ring.
Spherical cap calculator
Calculate the volume, base radius and surface areas of a sphere cut by a plane.
Conical frustum calculator
Find the volume and surface areas of a truncated right circular cone.
Rectangular pyramid calculator
Calculate a centred right pyramid’s volume, side areas and edge length.
Capsule volume & area
Measure a cylinder with two hemispherical ends.
Ellipsoid volume calculator
Calculate volume and axis lengths from three semi-axes.
Acceleration converter
Convert metres per second squared, standard gravity, feet and Gal.
Angular velocity converter
Translate RPM, revolutions per second, radians and degrees per second.
Volumetric flow converter
Convert liquid or gas volume rates, including L/min, CFM and gallons per minute.
Mass flow converter
Convert kg/h, g/s, tonnes per hour and pounds per minute.
Dynamic viscosity converter
Convert centipoise, poise, Pa·s and pound-mass viscosity units.
Kinematic viscosity converter
Convert centistokes, stokes and square length per second units.
Surface tension converter
Translate N/m, mN/m, dyn/cm and force per length.
Electric current converter
Convert amps, milliamps, microamps and nanoamps.
Electric charge converter
Convert coulombs, amp-hours, milliamp-hours and elementary charges.
Voltage converter
Convert volts, millivolts, microvolts, kilovolts and megavolts.
Electrical resistance converter
Translate ohms, milliohms, microohms, kilohms and megohms.
Electrical conductance converter
Convert siemens, millisiemens, microsiemens and mhos.
Capacitance converter
Convert farads, millifarads, microfarads, nanofarads and picofarads.
Inductance converter
Translate henries, millihenries, microhenries and nanohenries.
Magnetic flux converter
Convert webers, milliwebers, microwebers and maxwells.
Magnetic flux density converter
Translate tesla, millitesla, microtesla, nanotesla and gauss.
Illuminance converter
Convert lux, footcandles, kilolux, millilux and phot.
Luminance converter
Convert nits, candela per square metre, footlamberts and stilb.
Specific energy converter
Translate joules per kilogram, watt-hours per kilogram and BTU per pound.
Specific heat capacity converter
Convert J/(kg·K), kJ/(kg·K), calories per gram and BTU heat capacity units.
Thermal conductivity converter
Convert W/(m·K), milliwatts, BTU and calorie thermal conductivity units.
Thermal resistance converter
Convert K/W, degrees Celsius per watt and degrees Fahrenheit per BTU/hour.
Molar concentration converter
Convert mol/L, mmol/L, micromoles per litre and mol/m³.
Amount of substance converter
Convert moles, millimoles, micromoles, nanomoles and picomoles.
Frequency converter
Convert frequency units with clearly labelled standards.
Data transfer rate converter
Convert data transfer rate units with clearly labelled standards.
Density converter
Convert density units with clearly labelled standards.
Force converter
Convert force units with clearly labelled standards.
Torque converter
Convert torque units with clearly labelled standards.
Area converter
Convert area units with clearly labelled standards.
Volume converter
Convert volume units with clearly labelled standards.
Speed converter
Convert speed units with clearly labelled standards.
Time unit converter
Convert time unit units with clearly labelled standards.
Digital storage converter
Convert digital storage units with clearly labelled standards.
Angle converter
Convert angle units with clearly labelled standards.
Pressure converter
Convert pressure units with clearly labelled standards.
Energy converter
Convert energy units with clearly labelled standards.
Power converter
Convert power units with clearly labelled standards.
Descriptive statistics
Mean, median, mode, spread and standard deviation for your numbers.
Fraction calculator
Add, subtract, multiply or divide exact fractions.
Ratio simplifier
Reduce a ratio of whole numbers to its simplest form.
Percentage change
Find the increase or decrease from one value to another.
Random number generator
Generate unbiased whole numbers within your chosen range.
Prime number checker
Check whether a whole number is prime.
GCD & LCM calculator
Find the greatest common divisor and least common multiple.
Quadratic equation solver
Solve ax² + bx + c = 0, including complex roots.
Circle calculator
Find a circle’s area, diameter and circumference from its radius.
Rectangle calculator
Calculate area, perimeter and diagonal from two side lengths.
Triangle calculator
Find area and perimeter from three side lengths.
Pythagorean calculator
Find the hypotenuse of a right-angled triangle.
Text case converter
Change text to sentence, title, upper or lower case.
URL slug generator
Turn a title into a clean, readable URL slug.
Remove duplicate lines
Keep one copy of each line while preserving its order.
Sort lines
Sort lists alphabetically or by numeric value.
Whitespace cleaner
Tidy spaces and line endings without retyping your text.
Find & replace
Replace literal text safely, with optional case matching.
Text comparison
See which lines differ between two pieces of text.
Reading & speaking time
Estimate how long your text takes to read or say aloud.
Base64 encoder & decoder
Encode Unicode text to Base64, or decode it back.
URL encoder & decoder
Percent-encode a URL component or decode escaped text.
HTML entity encoder & decoder
Escape special characters or decode common HTML entities.
JSON formatter
Format or minify JSON and catch syntax errors.
SHA hash generator
Create SHA-256, SHA-384 or SHA-512 hashes of text.
Password generator
Generate random passwords on your device.
UUID generator
Generate random version 4 UUIDs.
Number base converter
Convert whole numbers between bases 2 to 36 exactly.
Basic Auth header generator
Create an HTTP Basic authorization header locally.
JWT decoder
Inspect a JSON Web Token’s header and payload locally.
Colour converter
Convert HEX, RGB and HSL colour values.
Colour contrast checker
Check text and background contrast against WCAG ratios.
Aspect ratio calculator
Simplify dimensions and resize proportionally.
Pixels & rem converter
Translate CSS pixels and rem using your chosen root size.
CSS gradient generator
Build a two-colour linear gradient and copy the CSS.
Add or subtract days
Move a calendar date forwards or backwards.
Day of the week
Find the weekday, day of the year and ISO week number.
Unix timestamp converter
Convert Unix seconds or milliseconds to a UTC date and back.
Age calculator
Calculate completed calendar years, months and days.
Weekday counter
Count Monday–Friday days between two dates.
CSV viewer
Open a CSV as a readable table, without uploading it.
CSV to JSON
Turn CSV rows into a JSON array of objects.
JSON to CSV
Convert a JSON array of objects into a downloadable CSV.
CSV crosstab
Cross-tabulate categories with counts, sums or averages.
Unit price calculator
Compare two pack sizes on the same unit basis.
Dice roller
Roll multiple dice with your chosen number of sides.
Fuel economy converter
Switch between mpg, litres per 100 km and km per litre.
Factorial calculator
Calculate exact factorials from 0! to 1000!.
Combinations & permutations
Count ordered or unordered selections without replacement.
Prime factorisation
Break a whole number into its prime factors.
Roman numeral converter
Convert whole numbers and canonical Roman numerals.
Number to words
Write whole numbers in British English.
Scientific notation converter
Express a number in standard and scientific notation.
Proportion calculator
Solve a / b = c / x for the missing fourth value.
Percentage difference
Compare two non-negative values symmetrically.
Weighted average
Calculate an average with a different weight for each value.
Simple linear regression
Fit a straight line to paired numeric observations.
Random list picker
Choose items from a list without picking the same line twice.
Random group generator
Shuffle a list into balanced groups.
Baking pan converter
Scale a recipe between round or rectangular baking pans.
Trip fuel cost
Estimate fuel quantity and cost from distance and consumption.
Pace calculator
Calculate pace and speed from a distance and finishing time.
Time duration calculator
Find elapsed time between two clock times.
Decimal hours converter
Convert decimal hours to hours:minutes:seconds and back.
Duration adder
Add a list of times, including negative durations.
Time zone viewer
See the same UTC instant in another time zone.
Text & binary converter
Encode UTF-8 text as binary bytes and decode it back.
Morse code translator
Translate letters and numbers to international Morse code.
Placeholder text generator
Create readable sample paragraphs for a layout.
Margin & markup calculator
Distinguish gross margin from markup on cost.
Break-even calculator
Estimate units needed to cover fixed and variable costs.
JSON viewer
Explore a collapsible JSON tree, search values, format and minify.
Image resizer
Resize an image to exact pixel dimensions, with a live preview.
Image format converter
Convert between PNG, JPEG and WebP on your device.
Image compressor
Adjust image quality and dimensions, then compare the file size.
Rotate image
Turn a photo by 90, 180 or 270 degrees.
Flip image
Mirror an image horizontally, vertically or both.
Crop image
Crop an image using precise pixel coordinates.
Merge PDFs
Combine PDF files in the order you choose, entirely on your device.
Extract PDF pages
Keep selected pages or ranges in a new PDF.
Rotate PDF pages
Rotate all or selected pages in a PDF.
QR code generator
Create a downloadable QR code for a link or short text.
BMI calculator
Calculate adult body mass index using metric or imperial measurements.
BMR calculator
Estimate the energy your body uses at rest with Mifflin–St Jeor.
TDEE calculator
Estimate daily maintenance energy from resting metabolism and activity.
Blood glucose converter
Convert blood glucose between mg/dL and mmol/L.
Cholesterol & triglyceride converter
Convert blood lipid units with the correct factor for each test.
HbA1c converter
Convert HbA1c between NGSP percent and IFCC mmol/mol.
Name wheel spinner
Add names, spin a colourful wheel and reveal a random winner with a little suspense.
Currency converter
Convert currencies with dated daily exchange rates, without fees or signups.
Paint calculator
Estimate wall paint, coverage and cost for a rectangular room.
Wallpaper calculator
Estimate whole rolls with drop length and pattern-repeat allowances.
Flooring pack calculator
Work out floor area, whole packs and estimated material cost.
Tile quantity calculator
Estimate tiles and whole boxes from area and tile dimensions.
Concrete volume calculator
Estimate concrete volume and bags using the stated bag yield.
Stair layout calculator
Explore riser count, tread count and straight stair run.
Room area planner
Add up multiple rooms and compare square metres with square feet.
Material cost calculator
Estimate quantities, delivery, tax and a project material total.
Ingredient cups & grams converter
Convert ingredient-specific US cups and grams in either direction.
Oven & fan temperature converter
Apply your chosen fan-oven adjustment in Celsius or Fahrenheit.
Baker’s percentage calculator
Express every ingredient relative to flour and scale a dough batch.
Sourdough hydration calculator
Include a starter’s flour and water in your total dough hydration.
Recipe cost calculator
Cost a recipe from pack prices and the quantities you actually use.
Cooking schedule planner
Work backwards from serving time for a sequence of kitchen tasks.
Multiple discount calculator
Apply successive discounts and see the effective overall saving.
Subscription cost calculator
Compare recurring charges on monthly and annual bases.
Savings goal calculator
Work out a monthly contribution or time to reach a savings target.
Compound interest calculator
Explore a savings balance with regular contributions and compounding.
Loan repayment calculator
Estimate fixed monthly payments and download an amortisation schedule.
VAT add & remove calculator
Add a supplied VAT rate or extract it from a gross price.
Images to PDF
Arrange PNG, JPEG or WebP images into one PDF on your device.
Add PDF page numbers
Add sequential footer numbers to all or selected PDF pages.
Watermark PDF
Add a translucent text watermark to all or selected PDF pages.
Reorder PDF pages
Put every PDF page into the exact order you choose.
Split PDF into pages
Download each PDF page as a separate file in one ZIP.
Favicon & ICO generator
Create an ICO and a complete downloadable favicon kit from text or an image.
Soil volume calculator
Estimate loose soil and whole bags for a rectangular area.
Raised bed fill calculator
Account for internal dimensions and unfilled space at the top.
Plant pot volume calculator
Estimate a tapered round pot’s internal capacity.
Mulch coverage calculator
See how far a bag or delivery will cover at your chosen depth.
Plant spacing planner
Lay out an evenly spaced rectangular planting grid.
Lawn seed quantity calculator
Estimate seed from area and the application rate on your pack.
Pond volume calculator
Estimate capacity from surface dimensions and average water depth.
Rainwater collection estimator
Translate rainfall and roof area into a potential collection volume.
Irrigation runtime calculator
Calculate the time needed to deliver a chosen water volume.
Seed tray planner
Estimate trays and seeds for a target number of seedlings.
Fence post calculator
Count posts and estimate actual equal spacing for a straight fence.
Decking board calculator
Estimate whole boards across a rectangular deck.
Gravel volume & mass calculator
Estimate loose aggregate volume, mass and whole bags.
Brick quantity estimator
Estimate rectangular wall bricks with mortar joints and openings.
Roof pitch calculator
Translate rise and horizontal run into an angle and rafter length.
Slope & gradient calculator
Compare gradient percentage, angle and rise-to-run ratio.
Appliance electricity cost
Estimate energy and cost from power, usage and your tariff.
Electricity bill estimator
Combine meter usage, unit price and a daily standing charge.
Image DPI & print size
See the physical print dimensions available at a chosen resolution.
Print size to pixels
Calculate required pixels for physical artwork dimensions.
Print bleed calculator
Add equal bleed around a trim size and see the artwork dimensions.
Typography scale calculator
Build a modular type scale around a base font size.
Video file size estimator
Estimate a video’s size from duration and combined bitrate.
CSS absolute unit converter
Translate CSS pixels, points, inches and metric absolute units.
Sphere calculator
Calculate a sphere’s volume and surface area from its radius.
Cylinder calculator
Find a right cylinder’s volume, curved area and total surface.
Cone calculator
Calculate volume, slant height and surface area of a right cone.
Cube calculator
Find a cube’s volume, surface area and space diagonal.
Cuboid calculator
Calculate a rectangular box’s volume, surface and space diagonal.
Trapezoid area calculator
Find area from parallel sides and perpendicular height.
Parallelogram area calculator
Use a base and its perpendicular height to calculate area.
Ellipse calculator
Calculate area and an approximate ellipse perimeter.
Regular polygon calculator
Find the area, perimeter and radii of a regular polygon.
Arc length calculator
Translate a circle’s central angle into an arc length.
Circular sector calculator
Calculate a sector’s area, arc and perimeter.
Polygon coordinate area
Calculate a simple polygon’s area from ordered coordinates.
Distance between two points
Find straight-line distance in a two-dimensional coordinate plane.
Midpoint calculator
Find the point halfway between two coordinate pairs.
Line slope calculator
Find a line’s gradient and intercept from two points.
Line equation evaluator
Evaluate y = mx + b and find its axis intercepts.
Linear equation solver
Solve a single equation of the form ax + b = c.
Two linear equations solver
Solve two equations in x and y using their coefficients.
Arithmetic sequence calculator
Find a term and partial sum of a constant-step sequence.
Geometric sequence calculator
Find a term and finite sum of a constant-ratio sequence.
Logarithm calculator
Calculate a logarithm in a chosen positive base.
Exponent calculator
Raise a number to a power with real-number validation.
Nth root calculator
Find a real positive- or odd-negative-number root.
Standard error of the mean
Summarise sample variability and the standard error of its mean.
Z-score calculator
Express a value in standard deviations from a supplied mean.
Percentile calculator
Find an interpolated percentile in a set of numbers.
Linear interpolation calculator
Estimate a y value on the line through two known points.
Add line numbers
Number text lines with a custom start and separator.
Text line wrapper
Wrap paragraphs to a chosen character width.
Reverse text or line order
Reverse characters, words or lines in plain text.
Unicode character inspector
Inspect code points, names for common controls and UTF-8 bytes.
Word frequency counter
Count repeated words with Unicode-aware word segmentation.
Remove combining accents
Create a text copy with Unicode combining marks removed.
List prefix & suffix
Add literal text before and after every line.
Text list to CSV
Turn one item per line into a safely quoted single-column CSV.
Transpose CSV
Swap a small CSV’s rows and columns.
Select CSV columns
Keep chosen columns and put them in a different order.
Filter CSV rows
Keep rows matching a literal text or numeric condition.
Sort CSV rows
Sort an export by one column while retaining its header.
Ohm’s law calculator
Calculate current and resistor power from voltage and resistance.
DC electrical power calculator
Relate voltage and current to power and energy over time.
Series & parallel resistors
Calculate ideal resistance in series or parallel.
Series & parallel capacitors
Calculate ideal capacitance in series or parallel.
RC time constant calculator
Estimate ideal resistor-capacitor charging and discharging.
Capacitor energy calculator
Find stored charge and energy from capacitance and voltage.
Charge from current & time
Translate a constant current and duration into electric charge.
Kinetic energy calculator
Find classical kinetic energy from mass and speed.
Gravitational potential energy
Calculate a near-surface energy change from a vertical height change.
Momentum calculator
Calculate one-dimensional classical momentum.
Average acceleration calculator
Find velocity change per unit time.
Newton’s second law calculator
Relate mass and acceleration to net force.
Constant acceleration calculator
Find velocity and displacement in a one-dimensional motion model.
Ideal projectile motion
Explore range, height and flight time for a level-ground model.
Wave speed calculator
Relate wavelength and frequency to wave speed.
Frequency & period calculator
Convert frequency into cycle period, or period into frequency.
Hooke’s law calculator
Find the restoring force for an ideal linear spring.
Spring energy calculator
Calculate elastic potential energy stored in an ideal spring.
Simple pendulum period
Estimate a small-angle pendulum’s period and frequency.
Pressure from force & area
Calculate average normal pressure on a surface.
Buoyant force calculator
Find ideal buoyancy from displaced fluid volume and density.
Ideal gas pressure calculator
Estimate absolute pressure from gas amount, volume and temperature.
Solution dilution calculator
Calculate stock volume for a target concentration and final volume.
Molarity calculator
Calculate concentration from solute amount and final solution volume.
Mass & moles calculator
Convert a mass and molar mass into amount of substance, or back.
Specific heat energy calculator
Estimate energy for a temperature change without a phase transition.
Linear thermal expansion
Estimate a length change using a supplied expansion coefficient.
Energy efficiency calculator
Compare useful energy output with total energy input.
Centripetal force calculator
Find the inward force required for uniform circular motion.
Work by a constant force
Calculate work from force, displacement and their angle.
Simple interest calculator
Estimate interest without compounding or additional payments.
Effective annual rate calculator
Compare a nominal annual rate with its compounded annual equivalent.
Inflation-adjusted return
Compare an effective return with inflation over the same period.
Inflation & purchasing power
Explore future prices and the present purchasing power of an amount.
Compound annual growth rate
Find the constant annual growth rate between two positive values.
Return on investment calculator
Compare final proceeds with the complete cost you supply.
Net present value calculator
Discount a series of end-of-period cash flows and subtract the initial cost.
Simple payback period
Estimate when non-negative periodic cash inflows recover an initial outlay.
Present value of regular payments
Discount a fixed series of equal end-of-period payments.
Savings withdrawal scenario
See how a constant monthly withdrawal changes a starting balance.
Loan overpayment calculator
Compare an additional monthly payment with a fixed-rate repayment schedule.
Fixed payment debt payoff
Estimate a payoff schedule from a balance, interest rate and monthly payment.
Cash runway calculator
Compare available cash with a constant monthly operating cash burn.
Working capital calculator
Calculate net working capital and the current ratio.
Inventory turnover calculator
Compare cost of goods sold with average inventory over one period.
Economic order quantity
Explore the basic constant-demand inventory order model.
Reorder point calculator
Combine expected demand during lead time with a supplied safety stock.
Marketplace fee & price calculator
See net proceeds or find a price for your target profit after fees.
Freelance hourly rate planner
Translate an annual revenue requirement into billable hours and a rate.
Gross salary equivalent
Translate annual gross pay into monthly, weekly, daily and hourly equivalents.
Overtime pay calculator
Calculate gross pay with a threshold and overtime multiplier you choose.
Advertising campaign calculator
Calculate CPC, CPM, conversion rate, CPA and ROAS together.
Sales funnel calculator
Compare stage counts and see step and overall conversion rates.
Customer acquisition cost
Compare acquisition expenditure with new customers over the same period.
Customer value scenario
Estimate gross customer profit from order value, frequency and lifetime.
Customer retention rate
Calculate retained customers after removing newly acquired customers.
Invoice line-item calculator
Total quantities and unit prices with a supplied discount, delivery and tax.
Tiered sales commission
Apply progressive commission rates to successive sales bands.
Parcel dimensional weight
Compare actual and volumetric weight using your carrier’s divisor.
Straight-line depreciation
Spread depreciable cost over a supplied useful life.
Assignment grade calculator
Combine assignment marks with optional weights and different maximum scores.
Required final exam grade
Find the final-exam percentage needed to reach a target overall grade.
Exam score with negative marking
Calculate an exam’s raw and percentage score from its marking scheme.
Credit-weighted GPA calculator
Calculate a GPA from course credits and grade points you supply.
Custom grade boundary checker
Map a percentage to a grading scale that you define.
Study time allocation planner
Divide a study-time budget between subjects using your own priorities.
Reading plan calculator
Turn a page target and daily budget into a manageable reading plan.
Flashcard session planner
Estimate a review session from card count, speed and planned breaks.
Attendance rate planner
See current attendance and how many consecutive attended sessions reach a target.
Video study time calculator
Estimate viewing time at a chosen playback speed with breaks.
Classroom group size planner
Split a class into groups with a maximum size or a chosen group count.
Scale drawing calculator
Convert model or drawing measurements to real dimensions and back.
Musical note frequency
Find a note’s frequency and MIDI number with adjustable concert pitch.
Frequency to musical note
Find the nearest equal-tempered note and its tuning offset.
Musical interval calculator
Compare two notes in semitones, octaves and frequency ratio.
Note list transposer
Move a list of octave-labelled notes by a chosen number of semitones.
Musical scale builder
Build a scale with correctly ordered note-letter spellings.
Chord note calculator
Find the notes and frequencies of common root-position chords.
Guitar fretboard note finder
List the notes across frets for your own open-string tuning.
Instrument fret position calculator
Calculate equal-tempered fret positions along a supplied scale length.
Ideal string tension calculator
Estimate tension from vibrating length, frequency and linear density.
Tempo & delay time calculator
Get straight, dotted and triplet note lengths for a quarter-note BPM.
Bars, beats & duration
Convert bars to elapsed time or elapsed time into bars and beats.
Audio file size estimator
Estimate uncompressed PCM size or fixed-bitrate encoded audio size.
Audio samples & time
Translate sample-frame counts and durations at a chosen sample rate.
Sample-rate playback change
See the pitch and duration effect of reinterpreting a recording’s sample rate.
Decibels & linear ratio
Convert gain in dB to a linear amplitude or power ratio, and back.
Add independent sound levels
Combine uncorrelated sound levels measured using the same reference.
Axial room mode calculator
Explore ideal axial resonances along a rectangular room’s three dimensions.
Speaker distance delay
Translate a path-length difference into an acoustic alignment delay.
Swing timing calculator
Split a pair of eighth notes into a chosen long-short timing ratio.
Polyrhythm timing grid
See where two equal subdivisions meet across one practice cycle.
Loudness gain & peak headroom
Estimate a gain-only loudness adjustment against a supplied true-peak ceiling.
Tempo speed-change calculator
Compare tempo, duration and pitch when playback speed changes.
Binomial probability calculator
Find exact and cumulative success probabilities for independent trials.
Poisson probability calculator
Explore event-count probabilities for a supplied average rate.
Normal interval probability
Find the probability inside and outside an interval under a normal model.
Normal percentile value
Find the value below which a chosen share of a normal distribution lies.
Uniform interval probability
Compare an interval with a continuous uniform distribution’s support.
Exponential waiting time
Estimate a waiting-time probability under a constant-rate model.
Trials until first success
Find the chance that the first success occurs on a particular trial.
Sampling without replacement
Find success-count probabilities when drawing from a finite population.
Bayes probability calculator
Update an event probability using evidence rates you supply.
Two-event probability calculator
Work out union, neither and conditional probabilities from an intersection.
Probability & odds converter
Translate an event probability into mathematical odds for and against.
Discrete expected value
Calculate an outcome distribution’s mean, variance and standard deviation.
Shared birthday probability
Explore the chance of a matching category in a group.
Survey sample size estimate
Plan a sample for a proportion using a supplied margin of error.
Wilson proportion interval
Calculate a bounded confidence interval for a count out of a sample.
Confidence interval for a mean
Estimate a mean interval using a sample and Student’s t distribution.
One-sample t test
Compare a numeric sample mean with a supplied reference value.
Welch two-sample t test
Compare independent sample means without assuming equal variances.
Paired sample t test
Compare matched observations by analysing their within-pair differences.
Chi-square goodness of fit
Compare observed category counts with expected relative weights.
Contingency table chi-square test
Compare two categorical variables using an observed count table.
Spearman rank correlation
Measure the association between two paired lists using ranks.
Independent-samples effect size
Compare two sample means in pooled standard-deviation units.
Geometric mean calculator
Average positive multiplicative values using logarithms.
Harmonic mean calculator
Average positive rates with an equal numerator basis.
Root mean square calculator
Calculate the quadratic magnitude of positive and negative values.
Trimmed mean calculator
Average a dataset after removing a chosen share from each end.
Median absolute deviation
Summarise spread using deviations from the sample median.
Interquartile outlier finder
List values outside configurable interquartile-range fences.
Coefficient of variation
Compare sample spread with its positive mean on a ratio scale.
Histogram frequency table
Bin a numeric list into equal-width intervals with cumulative counts.
Prediction error calculator
Compare matched actual and predicted values with common error measures.
Weighted median calculator
Find the first ordered value reaching half the total weight.
Min–max normalisation
Rescale a numeric dataset into a chosen output interval.
Standardise a numeric dataset
Convert each observation into a dataset-based standard score.
Moving average calculator
Smooth an ordered numeric series with a complete trailing window.
Join two CSV tables
Match rows across two tables using a shared identifier.
CSV grouped summary
Summarise a numeric column separately for each category.
Remove duplicate CSV rows
Keep the first row for each complete record or chosen key.
Fill empty CSV cells
Replace empty values across a table or in one column.
CSV column profile
Inspect missing values, distinct values and numeric summaries by column.
Rename CSV columns
Apply an explicit heading map while preserving cell contents.
CSV wide to long
Turn measurement columns into variable/value rows.
CSV long to wide
Turn identifier/variable/value records into a wider table.
Combine CSV tables
Append two tables with matching headings or align a union of their columns.
Add CSV row numbers
Add a sequential identifier column without changing the original cells.
Split a CSV column
Separate a cell into several columns using a literal separator.
Combine CSV columns
Join selected cells into a new column with your chosen separator.
Clean CSV cell whitespace
Trim cell edges or collapse internal whitespace without changing headings.
Find & replace in CSV cells
Replace literal text inside selected cells while keeping the table structure.
Round a CSV numeric column
Round decimal values with exact half-away-from-zero ties.
Extract unique CSV values
Export one column’s distinct values in first-seen or sorted order.
Sample CSV rows
Choose a random subset of complete rows without replacement.
CSV category frequency table
Count exact categories and compare their shares of a selected column.
CSV percentage of total
Append each numeric value’s share of its column total.
CSV running total
Append a cumulative numeric total in the table’s current order.
CSV lagged change
Compare each numeric value with an earlier row in the current order.
Extract CSV date parts
Add calendar fields from a strict ISO date column.
Latitude & longitude format
Translate signed decimal coordinates and degrees, minutes and seconds.
Great-circle distance & bearing
Compare two coordinates using a spherical Earth model.
Coordinate from distance & bearing
Find a spherical destination from a starting point and initial bearing.
Coordinate route distance
Add spherical leg distances along an ordered list of coordinates.
Latitude–longitude rectangle area
Estimate the spherical surface area inside geographic bounds.
Web Mercator coordinate converter
Convert decimal coordinates to or from EPSG:3857 map metres.
Geometric horizon distance
Estimate an unobstructed horizon from height above a spherical surface.
Walking & ascent time planner
Combine your walking pace, ascent allowance and planned breaks.
Humidity & dew point
Translate relative humidity and dew point with an over-water model.
Vapour pressure deficit
Compare air and leaf saturation pressure with actual air moisture.
Wind chill calculator
Estimate the NWS wind-chill index within its stated input range.
Heat index calculator
Combine air temperature and humidity using the NWS calculation.
Wind direction & components
Convert meteorological wind direction into east/north components, or back.
Dry-air sound speed
Estimate ideal sound speed from a supplied air temperature.
Exposure value calculator
Compare photographic settings on a logarithmic stop scale.
Equivalent shutter exposure
Keep a relative exposure while changing aperture and ISO.
ND filter exposure calculator
Translate filter stops into exposure time, factor and optical density.
Depth of field & hyperfocal
Explore thin-lens focus limits with a chosen blur criterion.
Camera field of view
Compare sensor dimensions, focal length and approximate scene coverage.
Macro extension estimate
Estimate magnification and exposure allowance from lens extension.
Flash guide number calculator
Relate ISO, direct-flash distance and aperture using a supplied guide number.
Light distance & falloff
Compare ideal point-source illumination at two distances.
EV charging time & cost
Estimate an energy top-up using average power, efficiency and your tariff.
Tyre size comparison
Compare nominal geometry and speed ratios for two metric radial sizes.
Wheel width & offset comparison
Compare nominal inner and outer rim-edge positions.
Cycling gearing calculator
Relate chainring, sprocket, wheel rollout and cadence to geometric speed.
Two-stroke fuel mix calculator
Work out oil and petrol quantities for a ratio you supply.
Vehicle ownership cost
Combine depreciation and your running-cost assumptions over an ownership period.
Focus & break session planner
Plan focus sessions with short breaks and an occasional longer break.
Meeting cost calculator
Estimate the value of attendee time using your own hourly rates.
Staff coverage lower bound
Compare required coverage hours with productive hours per person.
Work capacity planner
Translate a backlog and your working-time assumptions into throughput.
Rectangular box fit calculator
Compare uniform grid orientations of smaller boxes inside a larger box.
Backup storage estimate
Combine retained full and incremental payloads with supplied storage allowances.
File transfer time estimate
Estimate a transfer duration from file size, link rate and achieved efficiency.
Print job quantity & cost
Count printed pages and sheets, allowing for duplex copies.
Paper grid cutting layout
Compare portrait and rotated grid cuts with margins and gutters.
Weekly time budget
Add recurring activities and compare them with a 168-hour week.
Meeting availability overlap
Find shared time windows from several people’s same-day availability.
Timesheet hours calculator
Add work intervals and unpaid breaks from a local CSV.
Equal instalment plan
Split a remaining amount into cent-exact payments with due dates.
Shared expense settlement
Balance an equal-share expense pool and show suggested transfers.
Round-robin tournament schedule
Create match rounds and court/time slots without double-booking a team.
Seeded knockout bracket
Lay out a single-elimination bracket with explicit first-round byes.
League table calculator
Build standings from match scores and points rules you provide.
Elo rating change model
Explore expected scores and updates with your own scale and K factor.
Even-pace race split planner
Break a target distance and finish time into equal-pace splits.
Interval session planner
Add work, recovery, warm-up and cooldown blocks into a session plan.
A little room for your favourites.
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