Data & CSV

CSV dataset diff

Compare two keyed datasets and export exact record and cell changes.

Your inputs

Original / left CSV

Up to 25 MB per file, 50,000 data rows, 200 columns and 2 million data cells. Fully blank rows and columns are ignored before row, column and cell limits are checked. Individual tools may have smaller result or chart limits.

Or choose a CSV file

Left separator

Updated / right CSV

Or choose a CSV file

Right separator

Unique matching column

Results update as you type. Larger files run when you press Update result.

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Your result

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A clear answer. Here’s how.

Matches exact unique text keys, including blanks, and compares columns by heading rather than position. Both tables must have the same headings; duplicate keys are rejected. Reports added/removed whole records and changed cells, with up to 20,000 changes. Leading zeros and all cell strings are preserved. Original order drives removals/changes; new rows follow updated order.

See a worked example

Worked example

A fixed demonstration, separate from the values you enter above.

Original / left CSV

ID,Name
001,Ada
002,Sam

Left separator

Comma

Updated / right CSV

ID,Name
001,Ada
002,Samuel
003,Jo

Right separator

Comma

Unique matching column

Example result

Example result
Change	Key	Column	Before	After
Changed	002	Name	Sam	Samuel
Added	003	(record)		{"ID":"003","Name":"Jo"}

Exact cell strings, unique keys and heading names are compared. Column order may differ.