Convert Electrical Horsepower to Mechanical Horsepower
Convert Electrical Horsepower (hp(E)) to Mechanical Horsepower (hp) instantly and accurately.
Conversion Formula
hp = hp(E) × 1.000402479
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.
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.
Quick Reference Table
| Electrical Horsepower (hp(E)) | Mechanical Horsepower (hp) |
|---|---|
| 1 hp(E) | 1.0004 hp |
| 2 hp(E) | 2.0008 hp |
| 5 hp(E) | 5.00201 hp |
| 10 hp(E) | 10.004 hp |
| 25 hp(E) | 25.0101 hp |
| 50 hp(E) | 50.0201 hp |
| 100 hp(E) | 100.04 hp |