kW to Amps Calculator

Convert kilowatts to amps for single-phase or three-phase AC circuits using voltage and power factor.

Current (A) = Power (W) ÷ (Voltage × Power Factor) for single-phase, or ÷ (√3 × Voltage × Power Factor) for three-phase. A 10 kW single-phase load at 230 V with PF 0.9 draws 48.3 A.

Calculator

Power (kW)Real (active) power drawn by the load.Voltage (V)Single-phase: 230 V (AU/EU) or 120 V (US). Three-phase: enter line-to-line voltage — 400 V (AU/EU), 208 V or 480 V (US).Power factorRatio of real to apparent power. Resistive loads (heaters, elements): 1.0. Induction motors: 0.7–0.9. LED drivers: 0.9–0.95.Phase configuration

Full-load current

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How it works

Electrical power P = V × I × PF (single-phase) or √3 × V × I × PF (three-phase). Rearranging for current: I = P ÷ (V × PF) or I = P ÷ (√3 × V × PF). Entering kW multiplied by 1,000 converts to watts for the division.

Worked example

10 kW at 230 V single-phase, PF 0.9: I = 10,000 ÷ (230 × 0.9) = 48.3 A. Same load on 400 V three-phase: I = 10,000 ÷ (1.732 × 400 × 0.9) = 16.0 A — three-phase uses roughly one-third the current for the same power.

Assumptions & limitations

Uses RMS voltage and the real power formula for steady-state full-load current. Starting current for induction motors is typically 5–7× full-load amps — size circuit breakers and cable for starting conditions, not just running current. Results assume a balanced, sinusoidal load.

Frequently asked questions

What power factor should I use?

For purely resistive loads (electric heaters, incandescent lights, heating elements) use 1.0. For induction motors use 0.7–0.85 at full load. For LED drivers and VFDs use 0.9–0.95. If unknown, 0.9 is a conservative starting estimate for most industrial loads.

What voltage do I enter for three-phase?

Enter the line-to-line (phase-to-phase) voltage: 400 V in Australia and Europe, 208 V or 480 V in North America. Do not enter the phase-to-neutral voltage (230 V) for a three-phase calculation — that would give a result that is √3 too high.

How do I size a circuit breaker from this result?

Under AS/NZS 3000 (and NEC), a circuit breaker must be rated at ≥125% of the continuous full-load current. For 48.3 A: 48.3 × 1.25 = 60.4 A — select the next standard size up, typically a 63 A breaker.

What is the difference between kW and kVA?

kW is real (active) power — the useful work done. kVA is apparent power = kW ÷ power factor. A 10 kW load at PF 0.9 has an apparent power of 11.1 kVA. Transformer and generator ratings are in kVA, not kW, so always convert when sizing supply equipment.

Last updated 22 June 2026

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