VA ↔ Watts

How to use this calculator

Apparent power (VA) and real power (W) relate through the power factor: W = VA × PF and VA = W / PF. Enter a value in either field and a power factor between 0 and 1, and both update live. The power factor reflects how much of the current actually does useful work versus circulating due to phase shift.

What it means in a real circuit

Transformers and supplies are rated in VA, but loads consume W. A 1000 VA transformer at PF 0.8 delivers 800 W of real power; at PF 0.6 it delivers only 600 W even though it's carrying the same current. Use this to size a transformer for a load's real power and to understand why a low power factor wastes capacity and increases heating.