Power & phase

Amps to Watts Calculator

Real power equals voltage multiplied by current for DC. AC calculations also multiply by power factor and, for balanced three-phase power, by the square root of three.

Convert current to real power for DC, single-phase AC, and balanced three-phase AC.

Calculated result

Calculated real power

Calculating…

Calculated locally in your browser

Planning math only. Verify equipment specifications and installation requirements separately.

Amps to Watts Calculator relationship diagram. The illustration supports the text result; it is not a wiring or installation drawing.

What this calculator returns

The result is real power under the entered phase and PF assumptions.

Formula and variables

The calculation runs entirely in your browser. Static formulas, definitions, examples, and tables remain readable without JavaScript.

Formula

P = V × I (DC); P = V × I × PF (1φ); P = √3 × VLL × I × PF (3φ).

P: Real power, in watts or kilowatts.
S: Apparent power, in volt-amperes or kilovolt-amperes.
V: RMS voltage; line-to-line voltage in three-phase modes.
I: Line or circuit current, in amperes.
PF: Power factor, expressed as a ratio from greater than zero through one.
Q: Reactive power, in volt-amperes reactive.

P is real power; VLL is line-to-line voltage in three-phase mode.

Worked example

Worked example inputs
Input	Value
System type	Single-phase AC
Current	10 A
Voltage	240 V

240 V × 10 A × PF 0.8 = 1.92 kW for single-phase AC.

Reference table

Common-voltage conversion examples derived from P = V × I at power factor 1. Three-phase examples require the separate √3 relationship.
Voltage	Amps at 1 kW	Amps at 5 kW	Watts at 10 A
120 V	8.33 A	41.67 A	1,200 W
208 V	4.81 A	24.04 A	2,080 W
240 V	4.17 A	20.83 A	2,400 W
480 V	2.08 A	10.42 A	4,800 W

Frequently asked questions

How many watts is 10 amps at 240 volts?

At power factor 1, 240 volts times 10 amps is 2,400 watts in DC or single-phase AC.

Why does power factor lower the AC watt result?

Volts times amps gives apparent power; multiplying by power factor gives the real-power portion.

Assumptions and limitations

Balanced three-phase system assumed.
No protection or wiring recommendation.

Method and sources

Review the electrical formulas, calculation methodology, and reference tables for the references most relevant to this calculation. The broader technical sources index records source scope and verification. Last reviewed 2026-08-13.