Science & engineering
Ohm’s law calculator
Calculate current and resistor power from voltage and resistance.
A clear answer. Here’s how.
For an ideal ohmic resistor, current I = V/R and power P = V²/R. Voltage may be signed; resistance must be positive. Assumes a steady DC circuit and constant resistance, without temperature effects.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- DC voltage (V)
- 12
- Resistance (Ω)
- 100
Example result
- Current (A)
- 0.12
- Dissipated power (W)
- 1.44