hp to kW Converter (Horsepower to Kilowatts)
Convert horsepower to kilowatts for car registration, insurance and motor sizing. 1 hp = 0.7457 kW, so 150 hp is 111.85 kW and 300 hp is 223.71 kW.
Real-World Benchmarks
Multi-Unit Conversion Matrix
| Group | Measurement | Symbol | Equivalent Value |
|---|---|---|---|
| SI & Metric | Milliwatt | mW | 1.1185E8 |
| SI & Metric | Watt | W | 111,854.9807 |
| SI & Metric | Kilowatt | kW | 111.855 |
| SI & Metric | Megawatt | MW | 0.1119 |
| Horsepower | Mechanical Horsepower | hp | 150 |
| Horsepower | Metric Horsepower (PS) | PS | 152.0804 |
| Horsepower | Electrical Horsepower | hp(E) | 149.9397 |
| Thermal & Imperial | BTU per Hour | BTU/h | 381,665.0366 |
| Thermal & Imperial | Foot-Pound per Second | ft·lbf/s | 82,500 |
| Thermal & Imperial | Kilocalorie per Hour | kcal/h | 96,177.9714 |
| Thermal & Imperial | Ton of Refrigeration | TR | 31.8054 |
Step-by-Step Mathematical Explanation
- Step 1: Convert 150 hp to the base unit (W): 150 × 745.699871582 = 111,854.980737 W.
- Step 2: Convert base watts to kilowatts: 111,854.980737 ÷ 1,000 = 111.854981 kW.
- Direct factor: 1 hp = 0.74569987 kW.
Essential Conversion Factors
Mechanical Horsepower: US & UK imperial horsepower (550 ft·lbf/s)
hp to kW formula
Direct Answer: 1 hp = 0.74569987 kW, so multiply by 0.74569987: kW = hp × 0.74569987. Going back: hp = kW × 1.3410221.
How to convert mechanical horsepower to kilowatts
One mechanical horsepower is 550 ft·lbf/s, exactly 745.69987158 W. Multiply horsepower by 0.7457 to get kilowatts. If the figure is metric horsepower (PS, CV, ch), multiply by 0.7355 instead; the converter's unit list includes both.
1. hp → kW
Multiply the number of mechanical horsepower by the conversion factor:
Example: 150 hp × 0.74569987 = 111.85 kW.
2. kW → hp
To go back, divide by the same factor, or multiply by its reciprocal, 1.3410221:
Example: 111.85 kW ÷ 0.74569987 = 150 hp.
Mental math: take off a quarter
Subtract a quarter of the horsepower. The estimate is about 0.6% high:
200 hp: 200 − 50 = 150 kW (exact: 149.14 kW).
1 hp in other power units
| Unit | 1 hp equals | Typical use |
|---|---|---|
| Milliwatt | 745,699.87 mW | Lasers and radio transmitters |
| Watt | 745.69987 W | SI unit of power (1 J/s) |
| Kilowatt | 0.74569987 kW | Engines, EV motors and appliances |
| Megawatt | 0.00074569987 MW | Power plants and wind turbines |
| Metric Horsepower (PS) | 1.0138697 PS | European car ratings — PS, CV, pk |
| Electrical Horsepower | 0.99959768 hp(E) | Electric motor nameplates (746 W) |
| BTU per Hour | 2,544.4336 BTU/h | Air conditioners and furnaces |
| Foot-Pound per Second | 550 ft·lbf/s | Imperial mechanical power |
| Kilocalorie per Hour | 641.18648 kcal/h | Heating and metabolic rate |
| Ton of Refrigeration | 0.21203613 TR | Chiller and HVAC capacity (12,000 BTU/h) |
hp to kW chart
| hp | kW |
|---|---|
| 0.5 | 0.37 |
| 1 | 0.75 |
| 2 | 1.49 |
| 3 | 2.24 |
| 5 | 3.73 |
| 7.5 | 5.59 |
| 10 | 7.46 |
| 15 | 11.19 |
| 20 | 14.91 |
| 25 | 18.64 |
| 50 | 37.28 |
| 75 | 55.93 |
| 100 | 74.57 |
| 120 | 89.48 |
| 150 | 111.85 |
| 180 | 134.23 |
| 200 | 149.14 |
| 250 | 186.42 |
| 300 | 223.71 |
| 350 | 260.99 |
| 400 | 298.28 |
| 450 | 335.56 |
| 500 | 372.85 |
| 600 | 447.42 |
| 700 | 521.99 |
| 1,000 | 745.7 |
kW to hp chart
| kW | hp |
|---|---|
| 0.37 | 0.5 |
| 0.75 | 1.01 |
| 1 | 1.34 |
| 1.5 | 2.01 |
| 2.2 | 2.95 |
| 3 | 4.02 |
| 4 | 5.36 |
| 5 | 6.71 |
| 7.5 | 10.06 |
| 10 | 13.41 |
| 11 | 14.75 |
| 15 | 20.12 |
| 20 | 26.82 |
| 25 | 33.53 |
| 30 | 40.23 |
| 40 | 53.64 |
| 50 | 67.05 |
| 55 | 73.76 |
| 60 | 80.46 |
| 75 | 100.58 |
| 80 | 107.28 |
| 90 | 120.69 |
| 100 | 134.1 |
| 110 | 147.51 |
| 120 | 160.92 |
| 150 | 201.15 |
| 200 | 268.2 |
| 250 | 335.26 |
| 300 | 402.31 |
| 400 | 536.41 |
| 500 | 670.51 |
Frequently Asked Questions
What is 100 hp in kW?
100 hp is 74.57 kW (100 × 0.74569987).
What is 300 hp in kW?
300 hp is 223.71 kW (300 × 0.74569987).
How many kW is 1 horsepower?
One mechanical horsepower is 0.7457 kW (745.7 W). One metric horsepower (PS) is 0.7355 kW.
Why does my car's registration show kW instead of hp?
The kilowatt is the SI unit of power, and EU and Australian registration documents use it. Multiply the kW figure by 1.341 for hp or 1.360 for PS.