Type a value into any field and instantly see it converted across watts, kilowatts, mechanical horsepower, metric horsepower, BTU per hour and foot-pounds per second.
Runs entirely in your browser — nothing you enter is uploaded or stored.
Watts, kW, mechanical & metric horsepower, BTU/h and ft·lb/s all update together.
Keeps mechanical horsepower separate from metric horsepower (PS), which differ by 1.4%.
No accounts, no uploads — every calculation stays on your device.
Enter a power value in whichever unit you already have, and the rest fill in automatically.
Power is the rate at which energy is transferred, and it shows up in different units depending on the industry: electrical equipment is rated in watts and kilowatts, engines in horsepower, HVAC equipment in BTU per hour, and classical mechanics problems sometimes use foot-pounds per second.
This converter routes every value through watts as the SI base unit, using exact definitions: 1 mechanical horsepower = 745.6998715822702 W, 1 metric horsepower (PS) = 735.49875 W, 1 BTU per hour = 0.29307107017222 W, and 1 foot-pound per second = 1.3558179483314004 W.
Mechanical (imperial) horsepower is 745.7 W; metric horsepower (PS) is 735.5 W — a 1.4% difference that matters for car specs.
Air conditioner and heater capacity is commonly rated in BTU per hour in the US; 1 watt is about 3.412 BTU/h.
A classical mechanics unit equal to about 1.356 W, occasionally seen in older engineering texts and physics problems.
Power (watts) is a rate; energy (joules, kWh, BTU) is the total amount. Use the energy unit converter for the latter.
Common questions about converting between watts, horsepower and BTU per hour.
One mechanical (imperial) horsepower equals exactly 745.6998715822702 watts, commonly rounded to 746 W. This is the horsepower used for most car and engine ratings in the US and UK.
Mechanical horsepower is 745.6998715822702 W, while metric horsepower (PS, or cheval-vapeur) is 735.49875 W — about 1.4% smaller. European car specs often use metric horsepower.
One watt equals about 3.412142 BTU per hour, since 1 BTU per hour equals exactly 1,055.05585262 ÷ 3,600 = 0.29307107017222 watts.
Divide kilowatts by 0.7456998715822702 to get mechanical horsepower, or by 0.73549875 to get metric horsepower (PS).
No. Power is the rate energy is used or produced (energy per unit time), measured in watts. Energy itself is measured in joules, kilowatt-hours or BTU — use the dedicated energy unit converter for those.