Convert Mechanical Horsepower to Electrical Horsepower
Convert Mechanical Horsepower (hp) to Electrical Horsepower (hp(E)) instantly and accurately.
Conversion Formula
hp(E) = hp × 0.9995976831
About Mechanical Horsepower
The mechanical horsepower (hp) is exactly 550 ft·lbf/s ≈ 745.7 W - defined by James Watt by timing mine horses to set a comparable steam engine rating. A typical compact car produces 100-150 hp (75-112 kW); a sports car 300-600 hp; an F1 car ~1,000 hp (745 kW). SAE net horsepower is measured at the flywheel with all accessories fitted. Marine diesel engines, aircraft piston engines, and lawn equipment are still rated in hp. 1 hp = 550 ft·lbf/s = 745.6998715822704 W.
About Electrical Horsepower
The electrical horsepower (hp(E)) is defined as exactly 746 W - the US NEMA rounding used on electric motor nameplates. It differs from mechanical hp (745.7 W) by only 0.04%. Every NEMA-rated motor in the US carries a horsepower nameplate: a '5 hp motor' delivers 5 × 746 = 3,730 W. NEC motor branch-circuit sizing tables, overload relay selection, and starter ratings are all based on hp(E). Despite global kW adoption, US industrial motor infrastructure remains standardised in electrical horsepower. 1 hp(E) = 746 W.
Quick Reference Table
| Mechanical Horsepower (hp) | Electrical Horsepower (hp(E)) |
|---|---|
| 1 hp | 0.999598 hp(E) |
| 2 hp | 1.9992 hp(E) |
| 5 hp | 4.99799 hp(E) |
| 10 hp | 9.99598 hp(E) |
| 25 hp | 24.9899 hp(E) |
| 50 hp | 49.9799 hp(E) |
| 100 hp | 99.9598 hp(E) |