Power unit converter — kW, HP, kVA, amps
Convert power between kilowatts, horsepower and apparent kVA, and read the line current for single-phase or three-phase systems.
Power unit converter
Three-phase default 400 V (also common: 208, 230, 460, 690 V).
Factors: 1 hp = 0.7457 kW, 1 CV = 0.7355 kW, kVA × PF = kW. Line current: I = P × 1000 / (√3 × V × PF) three-phase, I = P × 1000 / (V × PF) single-phase.
Quick reference — common motor sizes
| kW | Imperial HP | Metric HP (CV) |
|---|---|---|
| 0.75 | 1.0058 | 1.0197 |
| 1.1 | 1.4751 | 1.4956 |
| 1.5 | 2.0115 | 2.0394 |
| 2.2 | 2.9502 | 2.9912 |
| 3 | 4.0231 | 4.0789 |
| 4 | 5.3641 | 5.4385 |
| 5.5 | 7.3756 | 7.4779 |
| 7.5 | 10.0577 | 10.1971 |
| 11 | 14.7512 | 14.9558 |
| 15 | 20.1153 | 20.3943 |
| 18.5 | 24.8089 | 25.153 |
| 22 | 29.5025 | 29.9116 |
| 30 | 40.2307 | 40.7886 |
| 37 | 49.6178 | 50.3059 |
| 45 | 60.346 | 61.1829 |
| 55 | 73.7562 | 74.7791 |
| 75 | 100.5766 | 101.9714 |
| 90 | 120.692 | 122.3657 |
| 110 | 147.5124 | 149.5581 |
Standard three-phase motor ratings from 0.75 to 110 kW, in both horsepower conventions.
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Frequently asked questions
How do I convert kW to amps for a three-phase motor?
Line current is I (A) = P × 1000 / (√3 × V × PF). With the default 7.5 kW, 400 V three-phase and 0.85 power factor, current is 7500 / (1.732 × 400 × 0.85) ≈ 12.7 A. Single-phase uses I = P × 1000 / (V × PF) with the default 230 V — 7500 / (230 × 0.85) ≈ 38.4 A. The converter switches both and shows the current at the line voltage you enter.
How is kVA different from kW?
Apparent power kVA is real power kW divided by the power factor: kVA × PF = kW. So the default 7.5 kW at 0.85 PF is 7.5 / 0.85 ≈ 8.8 kVA. The calculator converts kW, imperial hp (1 hp = 0.7457 kW), metric hp or CV (1 CV = 0.7355 kW), and kVA in any direction, which is useful when matching a motor kW rating to a transformer or generator kVA rating.
Why does the power factor matter for sizing a supply?
The line current a supply must carry depends on PF because the motor draws more apparent current than the real kW implies. This is why the three-phase default is 400 V at 0.85 PF and the single-phase default is 230 V — a typical industrial induction motor power factor. The default value of 7.5 kW also matches a standard motor frame size, so the current readout is realistic for a real installation.
AO Ctrl provides this tool for reference only.