Power Converter
Convert power between watts, kilowatts, megawatts, mechanical horsepower, metric horsepower and BTU per hour.
How it works
Power is energy per unit time — the rate of doing work, where energy is the total amount. A watt is one joule per second, and every unit here converts through the watt.
There are two horsepowers in common use and they differ by about 1.4%. Mechanical (imperial) horsepower is 745.7 W; metric horsepower, written PS or CV, is 735.5 W. Car specifications from different markets quote different ones, which is why the same engine can be advertised with two figures.
Do not confuse power with energy. A 2 kW heater running for three hours uses 6 kWh — the kilowatt is the rate, the kilowatt-hour is the total. Electricity is billed on the total.
The formula
kW → hp
hp = kW × 1.341
hp → kW
kW = hp ÷ 1.341
Any pair in this family
result = value × (factor of source ÷ factor of target)
Every unit is defined against the w, so any combination converts in one step.
Worked examples
| Scenario | Working | Result |
|---|---|---|
| 100 kW to horsepower | 100000 ÷ 745.7 | 134.1 hp |
| 100 PS to kW | 100 × 0.7355 | 73.55 kW |
| A 2 kW heater for 3 hours | 2 × 3 | 6 kWh of energy |
When you'd use it
- Comparing engine outputs quoted in hp and kW
- Sizing a generator or an appliance
- Converting HVAC ratings in BTU/h
- Physics and engineering coursework
Common questions
What is the difference between hp and PS?
Mechanical horsepower is 745.7 watts; metric horsepower (PS or CV) is 735.5 watts, about 1.4% less. A car listed at 150 PS is about 148 hp — the same engine, a different convention.
What is the difference between kW and kWh?
kW is a rate, kWh is a quantity. A 2 kW appliance draws 2 kilowatts while running; leave it on for three hours and it has consumed 6 kilowatt-hours. Your bill charges for the kWh.
How many watts are in a horsepower?
745.7 for mechanical horsepower. The figure comes from James Watt's estimate of what a dray horse could sustain, deliberately set high so his engines would not be over-sold against horses.
Is anything I enter sent anywhere?
No. Every conversion runs in your browser, so nothing you type is uploaded, logged or stored. There is no account and no record of what you converted.