How many watts are in one horsepower?

Mechanical horsepower, the common one for engines, is about 745.7 watts. Metric horsepower, used in much of Europe and often written PS or CV, is slightly less at about 735.5 watts. The small difference is why the same engine can be quoted with two slightly different horsepower numbers.

What is the difference between mechanical and metric horsepower?

They are two definitions of the same idea that came from different measuring systems. Mechanical (imperial) horsepower is about 745.7 watts; metric horsepower is about 735.5 watts, roughly 1.4 percent smaller. Car makers in metric countries usually quote metric horsepower or PS.

How accurate are the conversions?

Each conversion uses the exact, internationally defined factor for the unit, not a rounded approximation, so the maths is precise. The result is shown to several significant figures and rounded only for display. For everyday and most professional use, the figures are exact to well beyond the precision you need.

Does this work offline and is anything sent to a server?

The conversion runs entirely in your browser, so nothing you type is sent anywhere, and once the page has loaded it keeps working with no connection. There is no sign-up and no limit on how many conversions you make.

Power Converter

Convert power between watts, kilowatts, megawatts, mechanical and metric horsepower, and BTU per hour. Type a value and see it in every unit at once, exactly. A free power converter that runs in your browser.

Exact, standard factors
100% free
No sign-up, no app
Instant as you type
Works offline after first load

Convert

From

1.3410221hp

1 kW = 1.3410221 hp

1 kW in every unit

Watt1,000 W

Kilowatt1 kW

Megawatt0.001 MW

Horsepower (mech)1.3410221 hp

Metric horsepower1.3596216 PS

BTU per hour3,412.1416 BTU/h

How to use it

1
Enter a value

Type the number you want to convert. The result updates as you type, with no button to press.
2
Pick the units

Choose what you are converting from and to. Swap them with one click if you need the reverse.
3
Read or copy

See the exact result, plus a table of your value in every unit. Copy any line you need.

When it comes in handy

Cars and engines

Convert horsepower to kilowatts, or between mechanical and metric horsepower, when specs use different units.

Appliances and solar

Switch device or panel ratings between watts and kilowatts.

Heating and cooling

Convert BTU per hour to kilowatts when comparing air conditioners and heaters.

Instant, exact & 100% in your browser

The conversion runs right here in your browser using exact, standard factors. Nothing you type is sent to a server, there is no sign-up and no limit, and once the page has loaded it keeps working even with no connection.

Frequently asked questions

How many watts are in one horsepower?: Mechanical horsepower, the common one for engines, is about 745.7 watts. Metric horsepower, used in much of Europe and often written PS or CV, is slightly less at about 735.5 watts. The small difference is why the same engine can be quoted with two slightly different horsepower numbers.
What is the difference between mechanical and metric horsepower?: They are two definitions of the same idea that came from different measuring systems. Mechanical (imperial) horsepower is about 745.7 watts; metric horsepower is about 735.5 watts, roughly 1.4 percent smaller. Car makers in metric countries usually quote metric horsepower or PS.
How accurate are the conversions?: Each conversion uses the exact, internationally defined factor for the unit, not a rounded approximation, so the maths is precise. The result is shown to several significant figures and rounded only for display. For everyday and most professional use, the figures are exact to well beyond the precision you need.
Does this work offline and is anything sent to a server?: The conversion runs entirely in your browser, so nothing you type is sent anywhere, and once the page has loaded it keeps working with no connection. There is no sign-up and no limit on how many conversions you make.