Enter a real power in watts and a power factor to calculate the equivalent apparent power in volt-amps (VA).
How to Use the Watts to VA Calculator
Enter the device's real power in watts and its power factor (a decimal between 0 and 1), and the apparent power in VA updates as soon as either field changes.
Apparent power and real power measure two different things about the same circuit. Real power, in watts, is the energy actually doing work — spinning a motor, lighting a filament, heating an element. Apparent power, in volt-amps, is voltage multiplied by current: the full electrical load a circuit has to carry to deliver that real power, including the portion that sloshes back and forth without ever being converted into useful work. The two are tied together by the power factor:
Real Power (W) = Apparent Power (VA) × Power Factor
Apparent Power (VA) = Real Power (W) ÷ Power FactorA power factor of 1.0 means every volt-amp is doing useful work and the two figures match exactly; most real equipment — anything with a motor, transformer, or switching power supply — sits below that, commonly in the 0.6–0.9 range. Dividing by a number smaller than one always inflates the result, so VA is never less than W for the same device. That's not a rounding quirk, it's the whole point of the distinction.
It's also why a UPS, generator, or power strip is rated in VA rather than watts: the wiring and switching components inside have to survive the full current draw, not just the fraction that ends up doing useful work. Sizing one off a device's wattage label alone — ignoring power factor — is how people end up with a UPS that trips under a load it was supposedly rated to handle.