kW to Amps – 3 Phase Calculator
Convert kilowatts to amps for any three phase voltage system. Works for 400V, 415V, 480V, 208V or any custom voltage. Enter kW, line voltage, and power factor.
This calculator provides estimates only. Always consult a qualified electrician for real installations.
kW to Amps (Three Phase)
Result
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Line Current (Amps)
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Apparent Power (kVA)
Three Phase Formula
I = (kW × 1000) ÷ (√3 × Vline × PF)
Multiplier per kW at common voltages (PF = 0.85):
| Voltage | A per kW (PF 0.85) | A per kW (PF 0.9) | A per kW (PF 1.0) |
|---|---|---|---|
| 208V | 3.26 A/kW | 3.08 A/kW | 2.77 A/kW |
| 400V | 1.70 A/kW | 1.60 A/kW | 1.44 A/kW |
| 415V | 1.64 A/kW | 1.55 A/kW | 1.39 A/kW |
| 480V | 1.41 A/kW | 1.34 A/kW | 1.20 A/kW |
Frequently Asked Questions
What is the three phase kW to amps formula?
I = (kW × 1000) ÷ (√3 × V × PF), where √3 ≈ 1.732. The denominator for common voltages: 400V → 692.8 × PF, 415V → 718.8 × PF, 480V → 831.4 × PF. For 30 kW at 415V, PF=0.85: I = 30,000 ÷ (718.8 × 0.85) = 30,000 ÷ 611 = 49.1 A.
How does three phase current compare to single phase?
For the same load power, three phase uses about 57.7% of the current of single phase at the same phase voltage. For example, a 10 kW load: single phase at 230V requires 48.3 A; three phase at 400V requires only 16 A per phase. This reduction in current means smaller cables, less voltage drop, and lower copper losses.
What line voltage should I use in the formula?
Use line-to-line (phase-to-phase) voltage — 400V, 415V, 480V, etc. Never use phase-to-neutral voltage in the three phase formula. The relationship is: line voltage = phase voltage × √3. For 415V line voltage, phase-to-neutral is 415 ÷ 1.732 = 239.6V (≈240V).