# Horsepower to Amps Calculator

Enter horsepower, volts, and motor efficiency below to convert to amps.

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## How to Convert Horsepower to Amps

Horsepower (HP) is a measure of electric power equal to 746 watts (W). Converting horsepower to amps can be done in a few simple steps, or using this simple formula.

Amps = (Horsepower × 746) ÷ Efficiency ÷ Volts

Continue reading to see how this formula was derived.

### Convert Horsepower to Watts

The first step to convert HP to amps is convert HP to watts. Since 1 HP is equal to 746 W simply multiply the horsepower by 746 for this conversion.

Watts = Horsepower × 746

### Account for Efficiency

Since motors are not 100% efficient, the number of amps needed to achieve the power output is actually higher depending on the efficiency. To find this, divide the horsepower by the efficiency η in decimal form.

Watts = Watts / η

### Convert to Amps

After the power has been converted to watts, use the Watt’s Law formula to find current in amps.

Amps = Watts ÷ Volts

After the steps above the final formula for converting horsepower to amps is:

Amps = HP × 746 / V × η × PF

Thus, the current in amps is equal to horsepower times 746 divided by the voltage times the efficiency η times the power factor.

**For example,** let’s find the current draw in amps of a 1 horsepower motor that runs at 120 volts with a 90% efficiency.

Amps = 1 HP × 746 W / 120 V × .9

Amps = 746 / 120 V × .9

Amps = 746 / 108

Amps = 6.9 A

## Common Horsepower to Amps Conversions

Horsepower | Amps | Voltage | Efficiency |
---|---|---|---|

.25 HP | 1.73 A | 120 V | 90% |

.5 HP | 3.45 A | 120 V | 90% |

.75 HP | 5.18 A | 120 V | 90% |

1 HP | 6.91 A | 120 V | 90% |

1.25 HP | 8.63 A | 120 V | 90% |

1.5 HP | 10.4 A | 120 V | 90% |

1.75 HP | 12.1 A | 120 V | 90% |

2 HP | 13.8 A | 120 V | 90% |

2.5 HP | 17.3 A | 120 V | 90% |

3 HP | 20.7 A | 120 V | 90% |

3.5 HP | 24.2 A | 120 V | 90% |

4 HP | 27.6 A | 120 V | 90% |

4.5 HP | 31.1 A | 120 V | 90% |

5 HP | 34.5 A | 120 V | 90% |

10 HP | 69.1 A | 120 V | 90% |

Also be sure to check out our amps to horsepower calculator.