Motor Current Calculator
Use this motor full load current calculator to estimate single-phase and three-phase motor amps using horsepower or kilowatts, voltage, efficiency, and power factor.
This calculator provides an engineering estimate. Actual motor nameplate current can vary by motor design, service factor, efficiency class, starting method, and manufacturer. Always verify final values using motor nameplate data and applicable electrical code requirements.
1-Phase Current = (Power in Watts) / (Voltage × Efficiency × Power Factor)
Need help applying this to a real machine?
Get connected with a qualified automation integrator if you are sizing feeders, selecting controls hardware, planning a retrofit, or checking real electrical loads in a project.
Find an IntegratorQuick Motor Amps Reference
Approximate full load current values for common 3-phase motors at typical industrial voltages.
| Motor Size | 230V 3-Phase | 460V 3-Phase | 575V 3-Phase |
|---|---|---|---|
| 1 HP | 3.2 A | 1.6 A | 1.3 A |
| 2 HP | 6.0 A | 3.0 A | 2.4 A |
| 3 HP | 9.6 A | 4.8 A | 3.9 A |
| 5 HP | 15.2 A | 7.6 A | 6.1 A |
| 7.5 HP | 22.0 A | 11.0 A | 8.8 A |
| 10 HP | 28.0 A | 14.0 A | 11.2 A |
| 15 HP | 42.0 A | 21.0 A | 16.8 A |
| 20 HP | 54.0 A | 27.0 A | 21.6 A |
| 25 HP | 68.0 A | 34.0 A | 27.2 A |
| 30 HP | 80.0 A | 40.0 A | 32.0 A |
What this calculator helps with
This page is useful when estimating motor branch current, panel loading, contactor sizing, overload review, and feeder rough-in before final design details are locked down.
It is especially useful early in a project when you know the motor power but do not yet have final nameplate data. Once the actual motor is selected, always compare this estimate to the real nameplate current and any applicable electrical standards.