What is the difference between hp and PS?

Both are "horsepower", but mechanical hp (imperial) = 745.7 W, while metric horsepower PS (also cv/ch) = 735.5 W. So 100 PS ≈ 98.6 hp. European car specs usually quote PS; US/UK specs quote hp.

How many watts is one horsepower?

1 mechanical hp = 745.6998716 W ≈ 0.7457 kW (defined as 550 ft·lbf/s). 1 kW ≈ 1.341 hp, so a 100 kW motor is about 134 hp.

How do kW and BTU/h relate?

1 kW = 3,412.14 BTU/h, and 1 BTU/h = 0.293071 W. Air-conditioner and heater capacities are often given in BTU/h, so this is handy for HVAC sizing.

Is power the same as energy?

No. Power is the rate of energy use — energy per time. A 1-watt device uses 1 joule every second. Multiply power by time to get energy (e.g. 1 kW for 1 hour = 1 kWh).

Power Converter

Enter a power (rate of energy) in any common unit and see it in all the others instantly: milliwatt (mW), watt (W), kilowatt (kW), megawatt (MW), mechanical horsepower (hp), metric horsepower (PS, also called cv), BTU per hour (BTU/h), foot-pound per second (ft·lb/s), calorie per second (cal/s) and kilocalorie per hour (kcal/h). The value is converted to watts internally and then to every unit, so conversions are exact. Handy for cars and engines (hp ↔ PS ↔ kW), electricity and appliances (W, kW), heating and air-conditioning (BTU/h) and physics or engineering. Everything is computed locally in your browser.

—

ValueUnit

745,699.87

W (watt)

745.69987

0.74569987

0.0007457

hp (mechanical)

PS (metric hp)

1.0138697

BTU/h

2,544.4336

ft·lb/s

550

cal/s

178.22655

kcal/h

641.61557

How to use

Type a power value.
Pick the unit you entered it in.
Read the value in every other unit and copy whichever you need.

Frequently asked questions

What is the difference between hp and PS?: Both are "horsepower", but mechanical hp (imperial) = 745.7 W, while metric horsepower PS (also cv/ch) = 735.5 W. So 100 PS ≈ 98.6 hp. European car specs usually quote PS; US/UK specs quote hp.
How many watts is one horsepower?: 1 mechanical hp = 745.6998716 W ≈ 0.7457 kW (defined as 550 ft·lbf/s). 1 kW ≈ 1.341 hp, so a 100 kW motor is about 134 hp.
How do kW and BTU/h relate?: 1 kW = 3,412.14 BTU/h, and 1 BTU/h = 0.293071 W. Air-conditioner and heater capacities are often given in BTU/h, so this is handy for HVAC sizing.
Is power the same as energy?: No. Power is the rate of energy use — energy per time. A 1-watt device uses 1 joule every second. Multiply power by time to get energy (e.g. 1 kW for 1 hour = 1 kWh).

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