What this converter does
This converter turns real power in kilowatts into line current in amps for single-phase and three-phase AC circuits. Enter the voltage and power factor, pick the phase, and read the current — or swap the arrow to go from amps back to kW. It updates as you type.
Three-phase current uses the line-to-line voltage and a √3 factor; single-phase drops the √3. Power factor matters: a lower PF draws more current for the same kW. For apparent power instead, see the kW to kVA converter.
The units it covers
The current depends on three inputs beyond the power — the phase, the voltage and the power factor.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Real power | kW | P | The load, in kilowatts |
| Line current | A | I | What the conductor carries |
| Voltage | V | V | Line-to-line for three-phase |
| Power factor | PF | cos φ | Ratio 0–1, motor ≈ 0.8 |
The formula
Current is power divided by voltage, power factor and (for three-phase) √3:
A = kW × 1000 ÷ (√3 × V × PF) — drop √3 for single-phaseWhere:
- kW = real power delivered
- V = supply voltage (line-to-line for 3-phase)
- PF = power factor, 0 to 1
- √3 = 1.732, the three-phase factor
Worked example
A 100 kW three-phase load at 400 V and 0.8 PF. Find the current.
A = kW × 1000 ÷ (√3 × V × PF)100000 ÷ (1.732 × 400 × 0.8) = 180.4 AThe three-phase feeder carries about 180 amps at these settings.
The units in this example
The useful power the load consumes. Divided by voltage and power factor, it sets the current the cable and breaker must carry.
- 1 kW, 230 V, 1ph, PF 1 = 4.35 A
- 1 kW, 230 V, 1ph, PF 0.8 = 5.43 A
- 1 kW, 400 V, 3ph, PF 0.8 = 1.80 A
- kW = √3 × V × A × PF ÷ 1000
The amperes flowing in each line conductor. It sizes cables, breakers and protection, and rises as voltage or power factor falls.
- A = kW × 1000 ÷ (V × PF) — 1ph
- A = kW × 1000 ÷ (√3 × V × PF) — 3ph
- 1 A at 230 V, PF 1 = 0.23 kW
- √3 = 1.732