HP to kW Calculator
Convert horsepower ratings into kilowatts (kW) or vice versa. Swap variables using electrical, mechanical, or metric scaling types instantly.
Power Conversion Tool
How to Use the HP to kW Calculator
Converting output horsepower (HP) to active electrical power in kilowatts is direct.
- 1Enter Horsepower: Input the mechanical horsepower (HP) value into the designating field.
- 2Select HP Type: Choose Electrical, Mechanical/Imperial, or Metric from the dropdown.
- 3Calculate: Click the "Calculate to kW" button to run the conversion.
How to Convert HP to kW
In electrical design and motor application setups, power is often defined using mechanical metrics (horsepower) or metric grid metrics (kilowatts). Horsepower categories are defined by their physical load conversion constants, with electrical horsepower defined at exactly 746 Watts per HP. Sizing grid capacities or feeder lines requires applying these standard constants to convert HP nameplate values to equivalent active power in kW.
Real-Life Sizing Scenarios
Scenario 1: Sizing Active Power for a Cooling Pump Motor
An engineer plans the electrical supply for an industrial water circulation pump powered by a 15 HP electrical motor. Converting the motor's rated shaft output to kW (the supply must also cover motor losses: input kW = output kW ÷ efficiency):
Active Power (kW) = 15 HP × 0.746 kW/HP = 11.19 kW
Scenario 2: Sizing a Small Mechanical Boat Engine
An agricultural canal inspection boat uses a small outboard engine rated at 9.9 mechanical HP. Sizing the equivalent power capacity in kilowatts:
Active Power (kW) = 9.9 HP × 0.7457 kW/HP = 7.38 kW
Step-by-Step Manual Sizing Guide
- 1Identify Horsepower (HP): Check the nameplate mechanical power output.
- 2Identify HP Sizing Type: Determine if the motor rating represents electrical horsepower (746W), mechanical horsepower (745.7W), or metric horsepower (735.5W).
- 3Apply Conversion Constants:
- Electrical:
kW = HP × 0.746 - Mechanical:
kW = HP × 0.7457 - Metric:
kW = HP × 0.7355
- Electrical:
HP to kW Conversion Chart
The table below provides active power (kW) equivalents for common horsepower ratings across electrical, mechanical, and metric factors:
| Power (HP) | Electrical HP (0.746 kW) | Mechanical HP (0.7457 kW) | Metric HP (0.7355 kW) |
|---|---|---|---|
| 1 HP | 0.746 kW | 0.746 kW | 0.736 kW |
| 5 HP | 3.730 kW | 3.729 kW | 3.678 kW |
| 10 HP | 7.460 kW | 7.457 kW | 7.355 kW |
| 25 HP | 18.650 kW | 18.643 kW | 18.388 kW |
| 50 HP | 37.300 kW | 37.285 kW | 36.775 kW |
| 100 HP | 74.600 kW | 74.570 kW | 73.550 kW |
1 HP to kW
Converting a baseline mechanical rating of 1 HP to kilowatts depends on the type of horsepower. Under standard electrical motor designs, 1 HP is equal to exactly 0.746 kW, whereas mechanical (Imperial) horsepower is 0.7457 kW, and metric horsepower is 0.7355 kW.
10 HP to kW
Sizing the continuous electrical load for a 10 HP industrial pump motor. Sizing under standard electrical motor values:
Active power (kW) = 10 HP × 0.746 = 7.46 kW
5 HP to kW
A standard 5 HP compressor motor converts to electrical kilowatts to define grid active load requirements. Sizing at the electrical standard:
Active power (kW) = 5 HP × 0.746 = 3.73 kW
50 HP to kW
Sizing substation feeder capacities to match a large 50 HP mechanical motor load requires calculating active kW power. Sizing under electrical standards:
Active power (kW) = 50 HP × 0.746 = 37.30 kW
1.5 HP to kW
A small workshop ventilation fan motor rated at 1.5 HP draws electrical power based on its winding design. Sizing under the electrical horsepower factor:
Active power (kW) = 1.5 HP × 0.746 = 1.119 kW
7.5 HP to kW
Sizing circuit breaker feeds to accommodate a 7.5 HP electric motor requires converting the rating to active power. Sizing under electrical standards:
Active power (kW) = 7.5 HP × 0.746 = 5.595 kW
Frequently Asked Questions (FAQs)
To convert horsepower (HP) to active kilowatts (kW), multiply the HP value by the appropriate horsepower constant: kW = HP × 0.746 for electrical motor ratings.
No, one horsepower represents less power than a kilowatt. 1 electrical HP is equal to 0.746 kW (or 746 Watts), meaning that a kilowatt represents approximately 1.341 horsepower.
A 5 HP electric motor operates with an equivalent active capacity of: 5 HP × 0.746 = 3.73 kW.
A heavy locomotive or marine engine rated at 1000 HP produces: 1000 HP × 0.746 = 746 kW of mechanical power.
A 30 HP electrical motor converts to active power according to: 30 HP × 0.746 = 22.38 kW.
A 5 HP outboard motor installed on a standard 14-foot aluminum Jon boat typically reaches speeds of 10 to 15 mph (16 to 24 km/h) under normal weather conditions with one occupant and light gear.
