Power Converter
Convert power between watts, kilowatts, megawatts, the two different horsepowers, and BTU per hour. Car specifications are the usual reason: the same engine is quoted as 150 hp in the UK, 152 PS in Germany, and 112 kW on the type approval, and none of those numbers disagree with each other.
Converters
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How it works
Two horsepowers, one watt
1 hp = 745.6999 W · 1 PS = 735.49875 W · 1 BTU/h = 0.29307 W
Power is energy per unit time, and the watt is one joule per second. Both horsepowers are historical definitions that were later fixed against the watt, which is why neither is a round number and why they do not match each other.
- Mechanical horsepower is defined as 550 ft·lbf/s. Metric horsepower is defined as 75 kgf·m/s. Neither was derived from the other.
- PS (Pferdestärke), cv (cavalli/chevaux), and ch all mean metric horsepower — the same unit under different languages.
- A PS figure is always about 1.4% larger than the hp figure for the same engine, which is why brochures across markets seem to disagree.
- Electrical appliances are rated in watts directly, so no horsepower conversion is involved even for motors.
For reference
The same engine in three units
| kW | hp (mechanical) | PS (metric) |
|---|---|---|
| 55 | 73.8 | 74.8 |
| 82 | 110.0 | 111.5 |
| 112 | 150.2 | 152.3 |
| 150 | 201.2 | 203.9 |
| 360 | 482.8 | 489.5 |
Type approval documents in the EU quote kW, brochures quote PS, and the UK press quotes hp — all three describe one engine.
How to use
4 clear steps.
Enter the power figure you have.
Select its unit — mechanical hp and metric PS are separate entries.
Select the unit you want and read the converted value.
Use the full table to see the figure in every unit at once.
Good to know
Frequently asked questions
- How many kW is 1 hp?
- 1 mechanical horsepower is 0.7457 kW, so 1 kW is 1.341 hp. Metric horsepower (PS) is slightly smaller: 1 PS is 0.7355 kW, or 1.360 PS per kW.
- What is the difference between hp and PS?
- Mechanical horsepower (hp) is 550 foot-pounds per second, about 745.7 W. Metric horsepower (PS, cv, ch) is the power to lift 75 kg by one metre in one second, about 735.5 W. PS figures are therefore about 1.4% higher for the same engine.
- Why is my air conditioner rated in BTU?
- Heating and cooling capacity is traditionally quoted in BTU per hour. A 12,000 BTU/h unit is 3.52 kW of cooling — the same quantity in different units.