Ohm's Law Calculator
Enter any two of voltage, current, resistance, and power to solve the other two instantly with Ohm's law.
Processed locally in your browser — nothing is uploaded.
Enter any two values — the other two are solved from V = I·R and P = V·I.
Enter exactly two of the four values.
Formulas: V = I·R · P = V·I · P = I²·R · P = V²/R. Applies to DC and resistive AC loads.
About Ohm's Law Calculator
A four-way Ohm's law solver: type any two of V, I, R, and P and the remaining two are computed from V = I·R and P = V·I. The entered values stay highlighted so you can see at a glance which numbers were yours.
Common uses
- Find the resistance needed to limit current in a simple circuit
- Work out how many amps a heating element draws from its wattage
- Convert between watts and amps for a known supply voltage
Example
Input
V = 12 V, R = 6 Ω
Output
I = 2 A, P = 24 W
Limitations
- Assumes DC or purely resistive AC loads — reactive loads need power-factor math.