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Watts, Volts & Amps Calculator

Solve watts, volts or amps for DC or single-phase AC, with an explicit AC power factor and separate apparent power in VA.

1

Your inputs

Edit the example
V
A
PF

Use true power factor for your load. This is not inverter efficiency.

Example estimate · editable inputs

Real power

480 W

Apparent power
600 VA

Single-phase RMS values. Power factor is real W divided by apparent VA; it is not inverter efficiency.

BEHIND THE RESULT

How the calculation works

DC: P = V × I. Single-phase AC: real P = Vrms × Irms × PF. Apparent S = Vrms × Irms (VA). Rearrange to solve V or I using a nonzero denominator.

Watts and VA describe different aspects of AC demand. A watts-to-amps conversion needs both voltage and, for AC, power factor.

A worked example

120 V RMS × 5 A RMS × 0.8 power factor is 480 W of real power. Apparent power is 600 VA. At DC, 12 V × 5 A is 60 W.

What this estimate can’t tell you

Consumer-load, positive-power calculations only. No three-phase, wire, fuse, breaker or installation design. Does not certify a generator, inverter or outlet’s VA capability.

Sources & methodology

Formulas are derived from the units shown. Read our methodology or report a correction. Sources reviewed 2026-11-01.