Amps to Watts Calculator
Converts current in amps to power in watts for DC, AC single-phase and three-phase circuits — pick the circuit type, enter the voltage and power factor, and it solves the power.
Enter Values
Minimum 0
Minimum 0
Minimum 0
Range 0–1
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter any two of current (A), voltage (V) and power (W).
- Press Calculate — the third value is solved.
How it works
Power = current × voltage (W = V × A). Enter any two of the three and the calculator works out the rest.
Worked example
5 A at 240 V. = 1,200 W. And 1,200 W at 240 V = 5 A.
Common mistakes
- Forgetting the power factor on AC loads.
- Entering the wrong supply voltage.
Frequently asked questions
What's the formula?
Watts = volts × amps for DC or resistive AC. For AC motors, also multiply by the power factor.
Why doesn't it match my appliance's rating?
Real AC devices have a power factor below 1, so the actual watts are lower than volts × amps.
What about power factor on AC loads?
For resistive loads W = V × A. With motors and other reactive loads, real power = V × A × power factor (usually 0.8–1.0).
Related tools
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- Ohms Law Calculator
- Three Phase Power Calculator
- Power Factor Calculator
- Voltage Drop Calculator
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Cite this tool
Zerdly. (2026). Amps to Watts Calculator. Retrieved from https://www.zerdly.com/tools/amps-to-watts-calculator/
Tip: Enter any known values to calculate the remaining results.
Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.