When to Use This Calculator
Use this calculator when you know electrical real power in kW and need a steady-state current estimate for a DC load, single-phase AC load, or balanced three-phase AC load.
Enter Values
Formula Summary
DC: A = kW × 1000 ÷ V
Single-phase: A = kW × 1000 ÷ (V × PF)
Three-phase: A = kW × 1000 ÷ (√3 × V × PF)
For three-phase systems, voltage means line-to-line voltage.
Practical Examples
Single-phase heater and fan load
A 10 kW single-phase load at 240 V and 0.9 PF draws approximately 46.3 A.
Balanced three-phase load
A 75 kW three-phase load at 480 V and 0.85 PF draws approximately 106.2 A.
Real Power and Current
Power factor is required for AC loads because current carries both real and reactive components. At the same kW and voltage, lower power factor produces higher current.
For DC, power factor does not apply and the calculator uses kW divided directly by voltage.
Limitations
This result is steady-state current at the entered operating point. It does not include efficiency unless the entered kW already represents electrical input power.
Do not use calculated current alone for conductor, breaker, motor, generator, or equipment sizing.
Common Mistakes
- Entering mechanical output kW instead of electrical input kW.
- Using line-to-neutral voltage for a three-phase formula that expects line-to-line voltage.
- Assuming PF is 1.0 for motors, transformers, or mixed AC loads without data.
- Using running current as a code-compliant conductor or overcurrent-device size.
Reference Notes
The formulas are standard DC, single-phase AC, and balanced three-phase real-power relationships. Installation sizing may require equipment nameplates, manufacturer instructions, and the applicable electrical code, such as NFPA 70 in NEC jurisdictions.