Calculate voltage, current, resistance, or power using Ohm's Law. V=IR formula.
| Voltage (V) | — |
| Current (I) | — |
| Resistance (R) | — |
| Power (P) | — |
V = I×R | I = V/R | R = V/I | P = V×I = I²×R = V²/R. Enter any two known values and leave the others blank to calculate.