Last Updated on February 29, 2020 by Krunal Shah

This calculator is to find amps of AC motors. You can find amperes for both single phase and three phase motors when HP of motor is known to you.

**How to use the calculator?**

- From the drop down, select the phase.
- For this calculator, note down the voltage, efficiency, power factor and HP of the motor. You can find details from the motor nameplate.
- Enter the data collected in respective fields.
- You can take value 0.8 for pf and 0.8 for efficiency if it is not available on motor name plate.
- The calculator would show automatically the calculated value.

**How to calculate amperes when horse power is known?**

**Formula for Calculating amperes for single phase AC Motor**

For single phase, amperes (I) is equal to horse power (HP) multiply by 746 whole divided by Voltage (V) multiply by Power Factor (PF) multiply by Efficiency (EFF).

**Formula for calculating amperes for three phase AC Motor**

For three phase, amperes (I) is equal to horse power (HP) multiply by 746 whole divided by Voltage (V) multiply by Power Factor (PF) multiply by Efficiency (EFF) multiply by square root of 3.