Industrial Motor Sizing

Horsepower to Amps Calculator (HP to Amps)

Electric motor installation, pump sizing, industrial maintenance. Calculates motor full load current (FLA) using both exact formula and official NEC Table 430.248 (1-Phase) / 430.250 (3-Phase) lookup data.

⚡ Horsepower to Amps Calculator (HP to Amps)

Motor Horsepower (HP)

Supply Voltage (V)

Volts

Motor Phase (1 or 3)

Phase

Power Factor & Efficiency (default 0.85)

Ratio

Calculated Result

Instant Calculation

Engineering Output

Auxiliary Output

Step-by-Step Derivation ▼ Show Steps

Governing Formula Verified Physics

1-Phase: I = (HP × 746) / (V × η × PF) | 3-Phase: I = (HP × 746) / (√3 × V × η × PF)

Calculations adhere to standard electrical engineering physics and National Electrical Code (NFPA 70) regulations.

Engineering Principles & Calculations

This calculator uses the exact mathematical relationships between Motor Horsepower (HP: 1/4 HP to 500 HP), Voltage (115V, 208V, 230V, 460V, 575V), Phase (1Φ or 3Φ), Efficiency (default 85%), PF (default 0.85) to determine Full Load Current (Amperes), NEC Table Value, Recommended Overload Setting. In practical installations, factors such as ambient raceway temperature, harmonic distortion, duty cycle continuous operation, and conductor impedance must be accounted for by a certified electrician.

Calculates motor full load current (FLA) using both exact formula and official NEC Table 430.248 (1-Phase) / 430.250 (3-Phase) lookup data.

Typical Application & Industry Guidelines

Electric motor installation, pump sizing, industrial maintenance.

Reference Matrix