Amps to Watts Calculator — DC, AC Single-Phase, Three-Phase

Calculator

An amps to watts calculator finds real power (W) from current (A), voltage (V), and power factor (PF) for DC, AC single-phase, and AC three-phase circuits.

Amps to Watts Calculator

Runs in this browserUses the displayed formula

Inputs are calculated only in this browser. Three-phase uses line-to-line voltage; if the power factor is unknown, use 1 for resistive loads and 0.8-0.9 for motors.

Examples

Circuit type

Current

Voltage

Power

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What is it

Power is voltage times current. For DC, P = V × I; for AC single-phase, multiply by the power factor to get real power; for three-phase, also multiply by √3 using line-to-line voltage. It is commonly used to estimate load power from measured current when sizing breakers or wiring.

DC: P = V × I · AC single-phase: P = V × I × PF · AC three-phase: P = √3 × V × I × PF

How to use

1Pick the circuit type: DC, AC single-phase, or AC three-phase.
2Enter current (A) and voltage (V); for AC also enter the power factor.
3Press calculate to get the power in watts.

Reference

Amps to Watts Calculator — DC, AC Single-Phase, Three-Phase Reference
Current	Condition	Power
10A	DC 12V	120W
10A	AC 1-phase 220V, PF 0.9	1,980W
10A	AC 3-phase 380V, PF 0.9	5,924W

Sources & standards

BIPM — The International System of Units (SI Brochure) - BIPM
IEC Electropedia — International Electrotechnical Vocabulary - IEC
MDN Web Docs: Client-side web APIs - MDN Web Docs

FAQ

How many watts is 10 amps at 220 volts?

At power factor 1, P = 220 × 10 = 2,200W; at power factor 0.9 it is 1,980W.

What is the difference between real and apparent power?

Real power (W) does actual work, while apparent power (VA) is simply voltage times current. Their ratio is the power factor, and this calculator returns real power in watts.

Is amps to watts input sent to a server?

No. This calculator runs in your browser and does not send input to a server.