Power Calculator
Select a power formula (P=IV, P=V²/R, P=I²R, or P=W/t) and enter the known values to instantly calculate power in watts or solve for any variable.
Power Calculator
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Result
Select a formula and enter values to calculate power.
P = IV • P = V²/R • P = I²R • P = W/t
Formula Used
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Summary
Select a power formula (P=IV, P=V²/R, P=I²R, or P=W/t) and enter the known values to instantly calculate power in watts or solve for any variable.
How it works
- Select the formula tab that matches your known quantities.
- Choose unit prefixes (milli / base / kilo / mega) for each input.
- Enter known values; leave the unknown field blank.
- Click Calculate — the tool rearranges the formula algebraically to find the missing quantity.
- Review the result card showing the computed value, units, and exact formula used.
Use cases
- Calculate the power dissipated by a resistor in a circuit.
- Find the wattage of an appliance given its voltage and current draw.
- Determine mechanical power output from work done over time.
- Verify power ratings when designing electrical systems.
- Size fuses and circuit breakers by computing expected load power.
- Convert between related electrical quantities in student coursework.
Frequently Asked Questions
Last updated: 2026-06-09 ·
Reviewed by Nham Vu