Polytechnic Hub

Difference between watts and volt amperes

Volt ampere

Difference Watts

Valt-amperes

Abbreviation W VA
Calculation For dc: Vdc X Idc For dc: Vdc X Idc
Instrument need for measurement Wattmeter (a typical multimeter cannot measure watts unless the V and I are both dc) Typical multumeter capable of measuring VRMS and IrRMS.(VA = VRMS X I RMS)
Used for Evaluating heat generated or dissipated and calculating cost of energy. Properly sizing wires, circuit breakers, and fuses.
To add multiple rating together Add W ratings linearly No straightforward method to add VA, but if added linearly, result will be greater than or equal to actual total (adding linearly provides
a conservative estimate)