21 units · base unit W · M L² T⁻³

Power converter

There is no single horsepower. Mechanical, metric, electric and boiler horsepower all differ, and a car quoted at 200 PS is not quoted at 200 hp. All four are listed separately.

1000MW
✓ Exact 1 GW = 1000 MW
1 GW = 1000 MW

Common power conversions

All power units

Each unit expressed in watts (W), the unit everything in this category converts through.

Unit Symbol System Value in W
Terawatt TW metric 1000000000000
Gigawatt GW metric 1000000000
Megawatt MW metric 1000000
Kilowatt kW metric 1000
Watt W SI 1
Milliwatt mW metric 0.001
Microwatt µW metric 0.000001
Nanowatt nW metric 0.000000001
Horsepower (mechanical) hp imperial 745.699871582
Horsepower (metric) PS metric 735.49875
Horsepower (electric) hp (E) us 746
Horsepower (boiler) hp (S) us 9810.55407402
BTU per hour BTU/h imperial 0.293071070172
BTU per second BTU/s imperial 1055.05585262
Ton of refrigeration RT us 3516.85284207
Calorie per second cal/s metric 4.184
Kilocalorie per hour kcal/h metric 1.16222222222
Foot-pound per second ft·lbf/s imperial 1.35581794833
Erg per second erg/s cgs 0.0000001
Volt-ampere VA SI 1
Kilovolt-ampere kVA SI 1000

About power units

Convert watts, kilowatts, horsepower (mechanical and metric), BTU/h and tons of refrigeration.

There is no single horsepower. Mechanical, metric, electric and boiler horsepower all differ, and a car quoted at 200 PS is not quoted at 200 hp. All four are listed separately.

Dimensional formula: M L² T⁻³. Every conversion on this page goes through the watt, using exact fractions rather than decimal approximations. Read how that works →