Power and Resistance Calculator
⚡ Electricity & magnetism. Use the Power and resistance formula to find power, current, resistance: pick the value you want, type the others, and the answer updates as you go.
Power3 W
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Power | W |
| Current | A |
| Resistance | Ω |
Worked example
Find the power when Current = 0.5 A, Resistance = 12 Ω.
Using P = I²R: Power = 3 W.
Frequently asked questions
What is the formula for Power and resistance?
P = I²R.
What do the letters stand for, and what units are used?
Power in W, Current in A, Resistance in Ω.
How do you calculate power?
Put the values into P = I²R. For example, with Current = 0.5 A, Resistance = 12 Ω, power = 3 W.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (power, current, resistance) and fill in the others: it rearranges the formula for you.
