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.

Phase angle (deg)

Required number input.

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

Reactive power (var)

The resulting reactive 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.

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