Convert any power value between watts, kilowatts, megawatts, mechanical, metric and electrical horsepower, BTU per hour, tons of refrigeration and kilocalories per hour. Every unit updates as you type, with the formula shown.
Last updated:
Enter your values to see the result.
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How to use the Power Converter
Type the power value you want to convert.
Pick the From unit, for example horsepower or BTU/h.
Pick the To unit for the main answer; every other unit is listed below it.
Adjust the precision if you need more or fewer digits.
Copy the results or download the table as CSV.
Power unit conversion factors
Every conversion goes through the watt, the SI unit of power (1 W = 1 joule per second). Multiply by the first factor to get watts, then divide by the factor of the unit you want: result = value × factorfrom ÷ factorto. Example: 150 hp × 745.7 ÷ 1,000 = 111.85 kW.
Unit
1 unit in watts
Units per watt
Watts (W)
1 W
1
Kilowatts (kW)
1,000 W
0.001
Megawatts (MW)
1,000,000 W
0.000001
Horsepower, mechanical (hp)
745.699872 W
0.001341
Metric horsepower (PS, CV)
735.49875 W
0.00136
Electrical horsepower (hp(E))
746 W
0.00134
BTU per hour (BTU/h)
0.293071 W
3.41214
Tons of refrigeration (TR)
3,516.85284 W
0.000284
Kilocalories per hour (kcal/h)
1.163 W
0.859845
Foot-pounds per second (ft·lbf/s)
1.355818 W
0.737562
Which horsepower? And what is a ton of cooling?
Mechanical (imperial) horsepower, 745.7 W, is James Watt's 550 ft·lbf/s. US and UK car and engine ratings use it (often written bhp or just hp).
Metric horsepower (PS in Germany, CV in France, Italy and Spain) is 75 kgf·m/s = 735.5 W, about 1.4% smaller. European car brochures often quote PS, so 150 PS ≈ 148 hp ≈ 110 kW.
Electrical horsepower is exactly 746 W and appears on US electric-motor nameplates.
BTU per hour measures heating and cooling output (1 BTU/h = 0.293 W). A 5,000 BTU/h window air conditioner moves about 1.47 kW of heat; it is not the same as the electricity it consumes.
Ton of refrigeration is 12,000 BTU/h (3.517 kW), the heat needed to melt one short ton of ice in 24 hours. A 3-ton central AC removes about 10.55 kW of heat.
Kilocalories per hour (1 kcal/h = 1.163 W) are used for boilers, heaters and metabolic rates in many countries.
Everyday power examples
Example
Typical power
In other units
LED light bulb
9 W
30.7 BTU/h · 0.012 hp
Microwave oven (cooking power)
1,000 W
1 kW · 3,412 BTU/h · 1.34 hp
Window air conditioner (cooling)
12,000 BTU/h
3.52 kW · 1 TR
Compact car engine
100 kW
134 hp · 136 PS
Pickup truck engine
400 hp
298 kW · 406 PS
Large wind turbine
3 MW
4,023 hp · 10.2 million BTU/h
BTU here is the International Table BTU (1,055.056 J) and the kilocalorie is the International Table calorie (4.1868 kJ), the definitions used in engineering.
Frequently asked questions
How many watts are in 1 horsepower?
One mechanical (imperial) horsepower is 745.7 watts. One metric horsepower (PS) is 735.5 watts, and one electrical horsepower is exactly 746 watts.
How do I convert kW to hp?
Divide kilowatts by 0.7457 (or multiply by 1.341) to get mechanical horsepower. For example, 100 kW × 1.341 = 134.1 hp. For metric horsepower, multiply kW by 1.36.
How many BTU per hour is 1 kW?
1 kW equals about 3,412 BTU/h. To convert BTU/h to watts, multiply by 0.29307; for example, 12,000 BTU/h ≈ 3,517 W.
What is a ton of refrigeration in kW?
One ton of refrigeration is 12,000 BTU/h, which equals about 3.517 kW of cooling. It is based on the heat needed to melt one short ton of ice in 24 hours.
What is the difference between hp and PS?
Both are horsepower. The mechanical horsepower (hp) is 550 foot-pounds per second, about 745.7 W. The metric horsepower (PS or CV) is 75 kilogram-force metres per second, about 735.5 W, so 1 hp ≈ 1.014 PS.
Does an air conditioner rated 12,000 BTU/h use 3.5 kW of electricity?
No. BTU/h ratings describe how much heat the unit moves. Because air conditioners move more heat than the electricity they use, a 12,000 BTU/h unit typically draws roughly 1 to 1.5 kW of electrical power, depending on its efficiency.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.