Motor Amperage Calculator

Estimate Full Load Amps based on HP, voltage, phase, and typical/entered efficiencies & PF. Results update in real-time.

The Motor Amperage Calculator (Full Load Amps) Estimator helps calculate the approximate current a motor will draw under its rated load conditions. This is a crucial value for selecting appropriate wire sizes, circuit breakers, and other protective devices. The calculation is based on the motor's horsepower (HP), operating voltage, phase (single or three-phase), and optionally, its efficiency and power factor. If efficiency and power factor are not provided, typical values are used for estimation.

Motor Nameplate Information: A motor's nameplate is the primary source for its electrical characteristics. Key details usually include Horsepower (HP) or Kilowatts (kW), Voltage (V), Full Load Amps (FLA), Phase (PH), Frequency (Hz), RPM, Service Factor (SF), Efficiency (EFF), Frame Size, and Insulation Class. The nameplate FLA is the most reliable current value for design and troubleshooting.

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Important Disclaimer

This calculator provides an ESTIMATE. Actual Full Load Amps (FLA) can vary based on motor design and specific operating conditions. Always refer to the motor's nameplate for the accurate FLA value. For sizing conductors, overcurrent protection, and disconnects, consult the National Electrical Code (NEC) and a qualified electrician.