Ohm's Law Calculator
Ohm's law links voltage, current and resistance, and the power formula adds watts. Fill in any two of the four values and leave the others at zero.
Type a number and the answer appears straight away.
Power24 W
- Voltage
- 12 V
- Current
- 2 A
- Resistance
- 6 ohms
V = I x R and P = V x I.
The math behind it: Ohm's Law
V = I x R; P = V x I
A 12 volt supply pushing 2 amps means a resistance of 12 / 2 = 6 ohms and a power of 12 x 2 = 24 watts. Voltage is the push, current is the flow, and resistance is how hard the circuit makes it for current to flow.
Common questions
What is Ohm's law?
The voltage across a conductor equals the current through it multiplied by its resistance: V = I x R. Rearranged, I = V / R and R = V / I.
How do I calculate resistance?
Divide the voltage by the current. 12 volts driving 2 amps means 6 ohms of resistance.
How do I calculate watts from volts and amps?
Multiply them. 12 volts at 2 amps is 24 watts. Our amps to watts calculator does the same for household circuits.
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