Ohm's Law Calculator

Find current and power from voltage and resistance.

Current (A) 3

Power (W) 36

Formula: I = V ÷ R ; P = V² ÷ R

Step-by-step with your numbers:

1. Values used:

2. Voltage = 12 V

3. Resistance = 4 Ω

5. Current = Voltage / Resistance = 12 / 4 = 3A

6. Power = 36W

Did we solve your problem today?

Ohm's law links voltage, current and resistance in an electrical circuit.

The math behind it

V = I × R, so current I = V ÷ R. Power P = V × I = V² ÷ R.

12 V across 4 Ω → I = 3 A, P = 36 W.

What are the units?

Voltage in volts (V), current in amperes (A), resistance in ohms (Ω), power in watts (W).