How to convert kVA to amps
kVA is apparent power — volts times amps directly — so the current comes straight from the voltage, with no power factor in the way. Multiply kVA back to VA (× 1000), then divide by the voltage:
| System | Formula | Example |
|---|---|---|
| AC single-phase | I = kVA × 1000 ÷ V | 10 kVA, 240 V = 41.67 A |
| AC three-phase | I = kVA × 1000 ÷ (√3 × V) | 75 kVA, 480 V = 90.21 A |
The × 1000 turns kilovolt-amps into volt-amps. The √3 (about 1.732) in the three-phase formula comes from three-phase geometry — the same kVA draws fewer amps per line on a three-phase system.
kVA vs kW: why there's no power factor here
This is the mix-up worth clearing up. kVA is apparent power — the total the conductors actually carry. kW is real power — the useful work — and the two are linked by power factor: kW = kVA × PF. Because kVA already reflects the full current, you don't apply power factor when converting kVA to amps. Power factor only enters when you start from kW.
A 100 kVA load at a 0.8 power factor is 80 kW of real power — but it still draws the amps of the full 100 kVA. Size conductors and breakers from the kVA (the current), not the kW. If your number is in kW, run it through the kW to amps calculator instead.
Single-phase vs three-phase
Single-phase (120/240 V) divides by the voltage; three-phase (208/480 V) divides by an extra √3, so the same kVA pulls fewer amps per conductor. Here's 10 kVA across common systems:
| 10 kVA | Voltage | Amps |
|---|---|---|
| Single-phase | 120 V | 83.33 A |
| Single-phase | 240 V | 41.67 A |
| Three-phase | 208 V | 27.76 A |
| Three-phase | 480 V | 12.03 A |
Transformer full-load amps chart (kVA to amps)
This kVA to amps chart gives the three-phase full-load current for standard transformer sizes at 208 V and 480 V — the numbers behind "75 kVA to amps" and the like:
| Transformer | 208 V (3φ) | 480 V (3φ) |
|---|---|---|
| 15 kVA | 41.64 A | 18.04 A |
| 30 kVA | 83.27 A | 36.08 A |
| 45 kVA | 124.91 A | 54.13 A |
| 75 kVA | 208.18 A | 90.21 A |
| 112.5 kVA | 312.27 A | 135.32 A |
| 150 kVA | 416.36 A | 180.42 A |
| 225 kVA | 624.54 A | 270.63 A |
| 300 kVA | 832.72 A | 360.84 A |
For single-phase transformers, the same formula applies without √3 — a 25 kVA single-phase transformer at 240 V is 104.17 A, and a 50 kVA is 208.33 A.
Generators and UPS systems are usually rated in kVA, not kW — so this same calculator turns a genset or UPS rating straight into the output amps you can pull, which is what you match to a transfer switch, feeder, or panel. A 30 kVA standby generator at 208 V three-phase, for example, delivers about 83.27 A per line.
From kVA to the feeder (size the wire and breaker)
A transformer's secondary full-load amps — the number this calculator gives — is what sizes the secondary feeder and its protection. Continuous loads still follow the NEC 125% rule, and transformer overcurrent protection has its own rules in NEC 450.3, so a big install is worth an electrician's eye. Run the full-load amps through the Wire Size Calculator and the Breaker Size Calculator, and the AWG ampacity chart has the conductor ratings.
Frequently asked questions
ConversionsWhat is the formula to convert kVA to amps?
ConversionsHow many amps is 1 kVA?
ConversionsDoes kVA to amps use power factor?
ConversionsHow many amps is a 75 kVA transformer?
ConversionsHow many amps is 45 kVA at 480V?
ConversionsWhat is the difference between kVA and kW?
ConversionsHow do I convert kVA to amps for three-phase?
ConversionsHow many amps is 10 kVA?
This calculator gives estimates from the standard apparent-power formula. Transformer overcurrent protection and feeder sizing follow NEC 450.3 and your local authority having jurisdiction (AHJ) — always confirm against the code, and for larger installations, use a licensed electrician or engineer.