Power Converter

Convert power between watts, kilowatts, megawatts, horsepower and BTU per hour.

100% client-side · nothing is uploaded

Loading tool…

Quick answer

Power is a free, private online tool that lets you convert power between watts, kilowatts, megawatts, horsepower and BTU per hour. It runs entirely in your browser, so nothing you enter is uploaded to a server.

How to use the Power

Enter the number you want to convert in the Value field.
Pick the unit you're converting From and the unit you want To.
Read the converted result, or use ⇅ to swap the two units.
Check the All units table to see your value expressed in every supported unit at once.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About Power

Common power units

Watts and kilowatts (electrical and general), horsepower (engines), and BTU/hour (air conditioning).

Key conversions

1 hp is about 745.7 W. 1 kW is about 1.341 hp. 1 kW = 1000 W.

Where it helps

Comparing engine and motor outputs, sizing air conditioners, and electrical loads.

Frequently asked questions

How many watts in 1 horsepower?

About 745.7 watts (mechanical horsepower).

kW to hp?

Multiply kilowatts by about 1.341.

What is metric horsepower?

PS, about 735.5 W, slightly less than mechanical hp.

Understanding Power in depth

What power measures

Power is the rate at which energy is used or produced — energy divided by time. Where energy is measured in joules, power is measured in watts (one joule per second). It tells you how quickly work is done: a 2000-watt kettle uses energy twice as fast as a 1000-watt one. This converter moves a value across all the common power units.

How the conversion works

Every unit is defined relative to the watt, so the tool converts your value to watts and then to the target unit. The key ratios are: 1 kilowatt = 1000 W, 1 megawatt = 1,000,000 W, 1 mechanical horsepower ≈ 745.7 W, 1 metric horsepower (PS) ≈ 735.5 W, and 1 BTU per hour ≈ 0.293 W.

Horsepower and its variants

Horsepower was coined to compare engines to draft horses, and confusingly there are two flavours. Mechanical (imperial) horsepower is about 745.7 watts and is standard in the US and UK; metric horsepower, or PS, is about 735.5 watts and appears on European car specs. The small difference matters when comparing quoted engine outputs — 1 kW is about 1.34 hp.

Electrical and heating uses

Power ratings appear on almost every appliance. Electrical devices are rated in watts and kilowatts; air conditioners and boilers are often rated in BTU per hour, which converts to about 0.293 W each. Converting between kW and BTU/h is essential when sizing heating or cooling for a room.

Everyday uses

Compare engine and motor outputs across horsepower and kilowatts, size air conditioners and heaters rated in BTU/h, read appliance power ratings, and relate power to energy use (a 1 kW device run for 1 hour uses 1 kWh). Everything is calculated locally in your browser.