If you know power in kilowatts and need current in amps, this calculator gives you a fast and practical answer for single-phase, three-phase, and DC circuits. It is useful for panel sizing checks, breaker selection estimates, and quick electrical planning.
How the kW to amps conversion works
The current depends on system type, voltage, and (for AC) power factor. Use the following formulas:
1) Single-phase AC
2) Three-phase AC
3) DC
Where:
- I = current in amps (A)
- kW = real power in kilowatts
- V = voltage in volts
- PF = power factor (AC only)
Quick examples
| System | Inputs | Result |
|---|---|---|
| Single-phase AC | 5 kW, 230 V, PF 0.9 | 24.15 A |
| Three-phase AC | 15 kW, 400 V, PF 0.9 | 24.06 A |
| DC | 1.2 kW, 48 V | 25.00 A |
Why power factor matters
In AC systems, a lower power factor means higher current for the same real power. That affects cable heating, voltage drop, and apparent power demand. If you are uncertain, use your equipment nameplate value or consult manufacturer data.
Common mistakes to avoid
- Using the DC formula for AC loads.
- Forgetting power factor in AC calculations.
- Mixing line-to-line and line-to-neutral voltage in three-phase systems.
- Sizing wires or breakers exactly at calculated current with no design margin.
kW vs kVA (short clarification)
kW is real power (the useful part doing work). kVA is apparent power (total). They are related by:
If you only have kVA and PF, convert to kW first, then use this calculator.
FAQ
Can I use this for motor loads?
Yes for a quick estimate, but motors have starting current and duty considerations. Use nameplate full-load current and applicable code rules for final sizing.
What power factor should I use?
Use actual measured/nameplate PF when possible. If unknown, 0.9 is a common estimate for many modern loads.
Does this calculator include efficiency?
No. It converts from given real power (kW) to current. If your input power comes from mechanical output, account for efficiency before conversion.