Power Converter

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

Popular power conversions

Power unit reference chart

What one of each unit is worth in watts, the base unit used for every conversion in this category.

Power units expressed in watts
Unit	Symbol	1 unit in W
watts	W	1 W
kilowatts	kW	1,000 W
horsepower	hp	745.6998716 W
metric horsepower	PS	735.49875 W
megawatts	MW	1,000,000 W
BTU per hour	BTU/h	0.2930710702 W
milliwatts	mW	0.001 W
gigawatts	GW	1,000,000,000 W
foot-pounds per second	ft·lb/s	1.355817948 W

Power units explained

Watts (W)

The watt is the SI unit of power: one joule per second.

Kilowatts (kW)

A kilowatt is 1,000 watts. Electric motors, kettles, EV chargers and car engines outside the US are all rated in kilowatts.

Horsepower (hp)

Mechanical horsepower is defined as 550 foot-pounds per second, about 745.7 watts. It is the standard unit for engine output in the US and UK.

Metric horsepower (PS)

Metric horsepower, written PS or CV, is 735.49875 watts — slightly less than mechanical horsepower. European car makers quote it.

Megawatts (MW)

A megawatt is one million watts. Power stations, wind turbines and grid demand are all measured in megawatts.

BTU per hour (BTU/h)

BTU per hour rates the capacity of heaters and air conditioners. 12,000 BTU/h is one “ton” of cooling.

Frequently asked questions

What is the base unit of power?

This converter routes every power conversion through the watt. Converting from one unit to another means converting to watts first and then out again, which keeps every pair consistent with every other pair.

How accurate are these power conversions?

Results are shown to 10 significant digits using exact defined factors wherever a unit has one. No rounding is applied beyond that final display step.

All power conversions

Every power conversion page on this site, 50 in total.