### kVA: apparent power

kVA is a measure of *apparent power*: it tells you the total amount of power in use in a system. In a 100% efficient system kW = kVA. However electrical systems are never 100% efficient and therefore not all of the systems apparent power is being used for useful work output.

### kW: actual power

kW is the amount of power that *is* converted into a useful output. kW is therefore known as *actual power* or *working power*.

### Power Factor: a measure of electrical efficiency

You can convert between kVA and kW if you know the efficiency of the electrical system. Electrical efficiency is expressed as a power factor between 0 and 1: the closer the power factor is to 1, the more efficiently the kVA is being converted into useful kW. Generators have a power factor of 0.8.

The formula for **converting kVA into kW** is:

Apparent power (kVA) x power factor (pf) = actual power (kW)

*e.g. 100 kVA x 0.8 = 80 kW*

The formula for **converting kW into kVA** is:

Actual power (kW) / power factor (pf) = apparent power (kVA)

*e.g. 100 kW / 0.8 = 125 kVA*