kVA to amps calculator
Enter apparent power in kVA and the voltage. kVA already includes power factor, so no PF is needed.
Quick reference
| kVA | 208 V 3-ph | 480 V 3-ph | 240 V 1-ph |
|---|---|---|---|
| 15 kVA | 41.64 | 18.04 | 62.5 |
| 30 kVA | 83.27 | 36.08 | 125 |
| 45 kVA | 124.9 | 54.13 | 187.5 |
| 75 kVA | 208.2 | 90.21 | 312.5 |
| 112.5 kVA | 312.3 | 135.3 | 468.8 |
| 150 kVA | 416.4 | 180.4 | 625 |
| 225 kVA | 624.5 | 270.6 | 937.5 |
| 300 kVA | 832.7 | 360.8 | 1,250 |
| 500 kVA | 1,388 | 601.4 | 2,083 |
Full-load current for common three-phase transformer sizes.
The formulas
Single-phase: I = kVA × 1000 ÷ V and kVA = V × I ÷ 1000
Three-phase: I = kVA × 1000 ÷ (1.732 × VLL) and kVA = 1.732 × VLL × I ÷ 1000
kVA is apparent power. It is what transformers, generators and UPS units are rated in, because their heating depends on current whatever the power factor. To get real power: kW = kVA × PF.
Using the result safely
- Nameplate current beats a calculation. If the equipment lists amps, use that figure.
- For a load that runs 3 hours or more (EV charger, water heater, space heater), the NEC sizes conductors and breakers at 125% of the load.
- To pick the conductor for the current you found, go to the wire size calculator; for long runs check the voltage drop.
Questions people ask
How many amps is 75 kVA at 480 V three-phase?
75,000 ÷ (1.732 × 480) = 90.2 A on the primary. On a 208 V secondary it is 208.2 A.
Why is there no power factor in kVA to amps?
kVA is apparent power: volts × amps with no power factor applied. Current depends only on kVA and voltage.
kVA vs kW: what is the difference?
kW is real power that does work; kVA is apparent power the wiring must carry. kW = kVA × PF.