How to Convert Horsepower (HP) to Kilowatt-Hours (kWh)
One mechanical horsepower equals exactly 0.7457 kilowatts (745.7 Watts). Because horsepower represents mechanical power output and kWh represents electrical energy consumption over time, you calculate energy by converting HP to kW and multiplying by operating hours:
In practical motors, electrical efficiency is also factored in. Because motors experience thermal and magnetic losses (typically 80% to 90% efficient), the motor draws slightly more electrical power from the grid than its mechanical output rating:
Common Motor HP to kWh Consumption Table
| Motor Rating (HP) | kW Equivalent | kWh per Hour (100% load) | Daily kWh (4 hrs) |
|---|---|---|---|
| 0.5 HP | 0.37 kW | 0.37 kWh | 1.48 kWh |
| 1.0 HP | 0.75 kW | 0.75 kWh | 3.00 kWh |
| 1.5 HP | 1.12 kW | 1.12 kWh | 4.48 kWh |
| 2.0 HP | 1.49 kW | 1.49 kWh | 5.96 kWh |
| 3.0 HP | 2.24 kW | 2.24 kWh | 8.96 kWh |
| 5.0 HP | 3.73 kW | 3.73 kWh | 14.92 kWh |
Frequently Asked Questions
How many kW is 1 HP?
1 mechanical Horsepower equals approximately 0.746 kW (746 Watts).
How many kWh does a 1 HP motor use in an hour?
At 100% load and 85% motor efficiency, a 1 HP motor uses roughly 0.88 kWh per hour.
Why is HP used for motors and kW used for home appliances?
Horsepower originated with James Watt to compare steam engine power to draft horses, and remained standard in mechanical engineering. Modern electrical appliances use SI metric watts and kilowatts directly.
How do I calculate daily pump electricity cost from HP?
Multiply HP by 0.746, divide by efficiency (typically ~0.85), multiply by daily hours, and multiply by your electricity unit rate: Cost = (HP × 0.746 ÷ 0.85) × Hours × Rate.
