Calculate real, apparent and reactive AC power from voltage, current and power factor.
The power triangle relates apparent, real and reactive power. Only real power does useful work, but cables and transformers must be sized for apparent power, which is why a poor power factor costs capacity. Utilities charge for kVA capacity as well as kWh consumed, so improving power factor reduces billing even though the useful work is unchanged.
AC Power
S = V I; P = S cos φ; Q = S sin φ
S = V I; P = S cos φ; Q = S sin φ The power triangle relates apparent, real and reactive power. Only real power does useful work, but cables and transformers must be sized for apparent power, which is why a poor power factor costs capacity.
Utilities charge for kVA capacity as well as kWh consumed, so improving power factor reduces billing even though the useful work is unchanged.
This calculator takes 3 inputs: RMS voltage, RMS current, Power factor. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.