Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

RMS voltage (V)

Required number input.

RMS current (A)

Required number input.

Calculate apparent power in volt-amperes from RMS voltage and RMS current. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Apparent power (VA)

The resulting apparent power returned as a number.

• AC power calculations require a stated RMS convention and phase relationship. Nonsinusoidal waveforms, harmonics, unbalance, displacement versus true power factor, motor efficiency, and measurement bandwidth require waveform-aware analysis.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Reactive Power VAR

  Calculate signed reactive power in volt-amperes reactive from RMS voltage, RMS current, and phase angle.

• Real Power Watts

  Calculate real power in watts from RMS voltage, RMS current, and power factor.

• Ac Motor Reactive Power

  Calculate positive reactive-power magnitude for a balanced three-phase motor from line voltage, line current, and power factor.