Conversions
Horsepower to Watts Converter
Convert between horsepower and watts with mechanical (SAE), metric (PS), electrical (NEMA), and boiler (ASME) definitions. Includes kW and BTU/hr.
Horsepower / Watts Converter
Enter a non-negative hp value. Negative numbers are rejected; zero returns zero.
Used for engines, motors, and most US/UK power ratings.
Watts (W)
74,569.9872 W
Watts
74,569.9872 W
Kilowatts
74.57 kW
BTU per hour (mechanical hp)
254,443 BTU/hr
Same power expressed in each horsepower type
Mechanical (SAE)
100 hp
Metric / PS
101.387 hp
Electrical
99.9598 hp
Boiler (ASME)
7.601813 hp
Frequently Asked Questions about the Horsepower to Watts Converter
How many watts are in one horsepower?
It depends on the horsepower type. One mechanical (SAE) horsepower equals 745.6999 watts, one metric horsepower (PS) equals 735.49875 watts, one electrical horsepower equals 746 watts, and one boiler horsepower equals 9,809.5 watts.
What is the difference between mechanical, metric, and electrical horsepower?
Mechanical (or imperial / SAE) horsepower is the original James Watt definition used on US and UK car and engine ratings. Metric horsepower (PS, German Pferdestaerke) is slightly smaller at 735.49875 watts and dominates European engine specs. Electrical horsepower is rounded to exactly 746 watts and is the NEMA / IEEE convention for electric motor nameplates.
When should I use boiler horsepower?
Boiler horsepower (ASME) is a steam-industry unit equal to 9,809.5 watts, or 33,475 BTU/hr. It rates the heat output of steam boilers, not the shaft power of an engine, so use it only for steam-generation equipment.
How do I convert 100 horsepower to watts?
Using mechanical horsepower, 100 hp equals 74,569.99 watts, or about 74.57 kW. With metric horsepower, the same 100 PS equals 73,549.88 watts. Multiply the hp figure by the watts-per-hp factor for your selected type.
How many horsepower is 1000 watts?
1,000 watts (1 kW) equals about 1.341 mechanical horsepower, 1.360 metric horsepower, or 1.340 electrical horsepower. The converter shows all four equivalents at once so you can compare definitions directly.