Power Converter — Watts, Horsepower, kW & BTU/h
Convert watts to horsepower, kW to hp, PS, BTU per hour and tons of refrigeration. Exact NIST factors, free and instant.
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All units
| Unit | Value | Copy |
|---|---|---|
| WattW | 1000 | |
| KilowattkW | 1 | |
| MegawattMW | 0.001 | |
| Horsepower (mechanical)hp | 1.3410221 | |
| Horsepower (electric)hp(E) | 1.3404826 | |
| Metric horsepower (PS)PS | 1.3596216 | |
| Boiler horsepowerhp(S) | 0.101942 | |
| BTU per hourBTU/h | 3412.1416 | |
| Ton of refrigerationTR | 0.28434514 | |
| Foot-pound per secondft·lbf/s | 737.56215 | |
| Calorie per secondcal/s | 239.00574 | |
| Kilocalorie per hourkcal/h | 859.84523 |
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Frequently asked questions
How many watts are in one horsepower?
One mechanical horsepower (550 foot-pounds per second) is 745.7 watts. Electric-motor horsepower is defined as exactly 746 W, and metric horsepower (PS, CV, pk) is 735.5 W (NIST SP 811).
How do I convert watts to horsepower?
Divide the watts by 745.7. A 1,500 W space heater draws about 2.01 hp worth of power; a 250 W e-bike motor is about 0.34 hp.
How do I convert kW to hp?
Multiply kW by 1.341. A 150 kW car engine is about 201 hp, or 204 PS in metric horsepower (kW × 1.3596).
What is the difference between hp and PS?
Both describe engine power but use different definitions. PS (Pferdestärke) is 75 kgf·m/s = 735.5 W; mechanical hp is 550 ft·lbf/s = 745.7 W. So 100 PS ≈ 98.6 hp, and 100 hp ≈ 101.4 PS.
How many BTU per hour is one watt?
1 W ≈ 3.412 BTU/h, and 1 BTU/h ≈ 0.2931 W. A 12,000 BTU/h air conditioner (one ton of refrigeration) moves about 3,517 W of heat.
What is a ton of refrigeration?
It is 12,000 BTU per hour — originally the heat absorbed by melting one short ton of ice over 24 hours. It equals about 3.517 kW of cooling.