Electric Motor HP Chart
(Amps & kW)
Full-load amp (FLA) and kW reference for ¼ HP to 100 HP motors across all standard voltages. Use the FLA calculator to find amps for any custom HP rating.
Motor HP Reference Table
Full-load amps calculated using standard efficiencies and PF = 0.85. Always verify against the motor nameplate for wiring and protection sizing.
| HP | kW | 1φ FLA @ 115V | 1φ FLA @ 230V | 3φ FLA @ 230V | 3φ FLA @ 460V | 3φ FLA @ 575V |
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FLA Formula Explained
The NEC (National Electrical Code) publishes standard FLA tables in Article 430 that account for motor design variations. For circuit protection purposes, always use NEC table values or the actual nameplate FLA — not calculated values — when sizing breakers and conductors.
FLA values in the chart are calculated estimates using typical efficiencies (77–95% depending on HP) and PF = 0.85. Actual nameplate FLA may differ by 5–15%. For NEC compliance and circuit sizing, use NEC Table 430.248 (single-phase) or 430.250 (three-phase) values, or the actual motor nameplate.
Frequently Asked Questions
A 5 HP single-phase motor requires 230V single-phase. Three-phase 5 HP motors can run on 208V, 230V, 460V, or 575V depending on their winding configuration. Using 460V three-phase is preferred in industrial settings because it reduces current by half versus 230V, allowing smaller wire gauge and less heat loss in conductors.
For single-phase: FLA = (HP × 746) ÷ (V × Eff × PF). For three-phase: FLA = (HP × 746) ÷ (1.732 × V × Eff × PF). Use 90% efficiency and 0.85 power factor as defaults if nameplate values aren't available. Use the FLA calculator at the top of this page for quick results. Always verify against the nameplate for protective device sizing.
Power (watts) = voltage × current. Doubling voltage while delivering the same power halves the current. A 10 HP three-phase motor at 230V draws roughly 28A; the same motor at 460V draws only about 14A. This is why high-voltage wiring is preferred in industry — conductors can be smaller and line losses (I²R) are dramatically reduced.
Find your motor's horsepower row, then read across to your supply voltage and phase to get typical full-load amps and the kilowatt equivalent.
Power equals voltage times current, so for a fixed horsepower, higher voltage means proportionally lower current — which is why industrial motors often run at 480V.