kVA to Amps Calculator
Convert kVA to amps for single-phase and three-phase AC systems. This calculator is useful for generators, transformers, UPS systems, panels, and commercial electrical loads because it handles line-to-line voltage, line-to-neutral voltage, and amps back to kVA.
kVA to amps formulas
kVA is apparent power. It is widely used for generators, transformers, UPS systems, and commercial electrical equipment because it describes voltage and current capacity before power factor is applied.
Most three-phase supply voltages are stated as line-to-line values, such as 208 V, 400 V, 415 V, or 480 V. If your supply is written as 400/230 V, the 400 V value is line-to-line and the 230 V value is line-to-neutral.
Worked example: 25 kVA three-phase generator
A 25 kVA, 400 V three-phase generator can supply about 36 amps per phase before derating, overload limits, and load characteristics are considered.
Common kVA to amps reference table
| Rating | 230 V single-phase | 400 V three-phase | 480 V three-phase |
|---|---|---|---|
| 5 kVA | 21.74 A | 7.22 A | 6.01 A |
| 10 kVA | 43.48 A | 14.43 A | 12.03 A |
| 25 kVA | 108.70 A | 36.08 A | 30.07 A |
| 50 kVA | 217.39 A | 72.17 A | 60.14 A |
| 100 kVA | 434.78 A | 144.34 A | 120.28 A |
kVA, kW, amps, and power factor
The kVA value tells you the apparent electrical capacity. The kW value tells you the real usable power after power factor is considered. The relationship is kW = kVA × PF. For example, a 25 kVA generator at 0.8 power factor provides about 20 kW of real power.
Amps are different again: they describe current. To move from kVA to amps, you need voltage and phase. This is why the same 25 kVA rating produces different current values at 230 V, 400 V, and 480 V.
Common questions
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Multiply kVA by 1,000 to get volt-amps, then divide by the voltage factor. For single-phase, amps = kVA × 1000 ÷ V. For three-phase line-to-line voltage, amps = kVA × 1000 ÷ (√3 × V).
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For three-phase systems using line-to-line voltage, use A = kVA × 1000 ÷ (√3 × V). If you are using line-to-neutral voltage, use A = kVA × 1000 ÷ (3 × V).
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For single-phase AC, use A = kVA × 1000 ÷ V. A 10 kVA load at 230 V single-phase draws about 43.48 amps.
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25 kVA at 400 V three-phase line-to-line is about 36.08 amps, calculated as 25,000 ÷ (√3 × 400).
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50 kVA at 480 V three-phase line-to-line is about 60.14 amps, calculated as 50,000 ÷ (√3 × 480).
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Power factor does not change the kVA-to-amps current calculation because kVA is apparent power. Power factor is used when estimating kW from kVA, using kW = kVA × PF.
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No. kVA is apparent power, while kW is real power. They are equal only when the power factor is 1. At 0.8 power factor, 10 kVA equals 8 kW.
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Use the voltage type you actually have. Most three-phase supply ratings such as 208 V, 400 V, 415 V, and 480 V are line-to-line voltages. If your system is shown as 400/230 V, 400 V is line-to-line and 230 V is line-to-neutral.
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It gives the estimated current, but it should not be the only value used for breaker sizing. Breaker and cable selection also depend on load type, duty cycle, starting current, ambient conditions, derating, and local electrical code.
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Generators and transformers are commonly rated in kVA because their heating and capacity depend strongly on voltage and current. The real kW output depends on the connected load power factor.