Power Converter: kW, hp, BTU/h, kcal/h

Written byOleh Soloninupdated 5 October 2026

Value

From

Result

Result135.962162
From unitkilowatt
To unitmetric horsepower
Conversion factor1.359622
Inverse factor0.735499
In other units
watt: 100,000 megawatt: 0.1 mechanical horsepower: 134.1 BTU per hour: 341,214.16 kilocalorie per hour: 85,984.52 gigacalorie per hour: 0.085985 foot-pound per second: 73,756.21

1 kW = 1.341 hp (mechanical) or 1.360 PS (metric)

Converts kilowatts to horsepower and back, along with watts, megawatts, BTU per hour and kilocalories or gigacalories per hour, keeping metric and mechanical horsepower apart, with a table of common engine outputs.

Mechanical horsepower, defined as 550 foot-pounds per second, is 745.6999 W, so 1 kW = 1.341 hp and 100 kW = 134.1 hp. Metric horsepower (PS, the Russian л. с.) is smaller, 735.49875 W: 100 kW is 135.96 metric horsepower.

BTU per hour is how air conditioners are rated: 9,000 BTU/h is 2.64 kW. The gigacalorie per hour, used for boilers and district heating in Russia, is 1.163 MW.

How to use

Enter the power value.
Pick the unit to convert from and to, for example kilowatts to mechanical horsepower.
Read the result, the conversion factor both ways and the same value in every other unit.

Horsepower and kilowatts

Kilowatts to mechanical horsepower: multiply by 1.34102. Mechanical horsepower to kilowatts: multiply by 0.7457. For metric horsepower the factors are 1.35962 and 0.7355.

Metric horsepower is 75 kilogram-force metres per second: 75 × 9.80665 = 735.49875 W. Mechanical horsepower is 550 foot-pounds per second, 745.6999 W. The two differ by about 1.4%.

Metric horsepower, 1 PS = 735.49875 W. Worked out with this converter.
Metric horsepower	Kilowatts
70 PS	51.48 kW
90 PS	66.19 kW
100 PS	73.55 kW
110 PS	80.9 kW
120 PS	88.26 kW
150 PS	110.32 kW
200 PS	147.1 kW
250 PS	183.87 kW
300 PS	220.65 kW

BTU per hour, kilocalories and gigacalories

1 BTU per hour is 0.2930711 W (the International Table BTU), so 12,000 BTU/h is 3.52 kW. A kilocalorie per hour is 1.163 W and a gigacalorie per hour 1.163 MW, with the International Table calorie of 4.1868 J.

The factors come from NIST Special Publication 811, Appendix B.9.

NIST Special Publication 811, Appendix B.9.
Unit	In watts
1 metric horsepower	735.49875 W
1 mechanical horsepower (550 ft·lbf/s)	745.6999 W
1 BTU per hour	0.2930711 W
1 kcal per hour	1.163 W
1 Gcal per hour	1,163,000 W
1 foot-pound per second	1.355818 W

What this calculator shows

The conversion between the two units you picked
The conversion factor in both directions
The same value in every other unit on the list

What to keep in mind

Metric horsepower is 735.49875 W and mechanical horsepower 745.6999 W (NIST SP 811).
The BTU and the calorie are the International Table units: 1 BTU/h = 0.2930711 W, 1 cal = 4.1868 J.

Where the numbers come from

Checked against NIST Special Publication 811, Appendix B.9 (horsepower, BTU, IT calorie) · verified September 2026.

FAQs

How many kilowatts in one horsepower?

0.7457 kW in mechanical horsepower (745.6999 W) and 0.7355 kW in metric horsepower (735.49875 W).

How do I convert kW to hp?

Multiply by 1.34102 for mechanical horsepower or 1.35962 for metric. 100 kW is 134.1 hp or 135.96 PS.

How many kW is 1 Gcal/h?

1,163 kW, or 1.163 MW: a gigacalorie is 10⁹ calories of 4.1868 J each, spread over the 3,600 seconds of an hour.

What is BTU per hour?

British thermal units per hour, the unit air conditioners are sold by. 1,000 BTU/h is 293.07 W, and 9,000 BTU/h is 2.64 kW.

Why are there two horsepowers?

Metric horsepower was defined in kilogram-force, 75 kgf·m/s, and mechanical horsepower in foot-pounds, 550 ft·lbf/s. They differ by about 1.4%.

Is power the same as energy?

No: power is energy per unit of time. A 2 kW heater running for three hours uses 6 kWh of energy — watts on the label, kilowatt-hours on the bill.

Worked example

A hundred kilowatts in horsepower

Input: 100 kW to metric horsepower

Output: 135.96 PS

Note: In mechanical horsepower it would be 134.1, about 1.4% less, because the mechanical unit is the larger one.

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Power Converter: kW, hp, BTU/h, kcal/h

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