Horsepower to Watts
Convert horsepower to watt instantly — type a value and read the result, with the exact formula shown.
Example
1 hp = 745.6999 W, 5 hp = 3,728.499 W, 10 hp = 7,456.999 W.
How it works
Watt = Horsepower × 745.6999. Every value is converted through a single watt base unit using internationally defined conversion factors, so any from/to pair stays consistent.
Good to know
Converting horsepower to watts shows up whenever a mechanical power rating needs to be expressed in standard electrical or SI units. You hit it when sizing a backup generator for a pump, spec'ing the wattage draw of an electric motor that's labeled in hp, comparing a car or compressor's output across regions, or working through a physics homework problem that mixes imperial and metric power.
The two units come from different eras and systems. Horsepower was coined by James Watt in the late 1700s to sell steam engines against draft horses, and the mechanical horsepower used here is defined as 550 foot-pounds per second, an imperial unit. The watt is the SI unit of power (one joule per second) and was named after Watt himself, which is why 1 hp resolves to the somewhat awkward 745.6999 W rather than a round number.
A handy rule of thumb: 1 hp is roughly three-quarters of a kilowatt, so you can mentally estimate by multiplying hp by 750 (or by 0.75 for kilowatts). A 100 hp engine is about 75 kW, and a 5 hp motor is close to 3,728 W. For quick math, multiplying by 746 is accurate to four significant figures.
The most common mistake is assuming all "horsepower" is the same. This converter uses mechanical (imperial) horsepower at 745.6999 W, but metric horsepower (PS/CV, common on European car specs) is only 735.5 W, and electrical horsepower is exactly 746 W. Pick the wrong definition and your result drifts by over 1 percent, which matters when you're sizing wiring or a generator with little headroom.
Frequently asked questions
How do you convert horsepower to watt?
Multiply the number of horsepowers by 745.6999 to get watts. For example, 1 hp = 745.6999 W.
What is 1 horsepower in watts?
1 horsepower equals 745.6999 watts (1 hp = 745.6999 W).
How many horsepowers are in 1 watt?
There are 0.001341022 horsepowers in 1 watt.
Is this converter free and private?
Yes. It runs entirely in your browser, so your inputs never leave your device, there is no sign-up, and it works offline once loaded.
Are the conversions exact?
Conversions use internationally defined factors and are exact where the definitions are exact (for example, 1 inch = 2.54 cm). Displayed results are rounded for readability.
People also ask
How many watts is a 1 hp motor?
A 1 hp motor is rated at 745.6999 W, usually rounded to about 746 W. Note this is the mechanical output rating; the actual electrical draw is higher because no motor is 100 percent efficient.
Is 1 hp equal to 746 watts or 750 watts?
Mechanical (imperial) horsepower is exactly 745.6999 W, which rounds to 746 W. The 750 W figure is just a convenient rough estimate, not an official definition.
How do I convert 5 hp to watts?
Multiply 5 by 745.6999 to get 3,728.5 W (about 3.73 kW). For a quick estimate, 5 times 750 gives you roughly 3,750 W.
What is the difference between metric horsepower and mechanical horsepower in watts?
Mechanical (imperial) horsepower equals 745.6999 W, while metric horsepower (PS or CV) equals only 735.5 W. That is about a 1.4 percent difference, so check which one a spec sheet uses.
How many watts is 100 hp?
100 hp equals 74,569.99 W, or about 74.57 kW. A fast mental estimate is 100 times 750, which gives 75,000 W.
Why is 1 horsepower not a round number of watts?
Because horsepower is defined in imperial units (550 foot-pounds per second) while the watt is metric (one joule per second). Converting between the two systems produces the irregular factor 745.6999.
Does electrical horsepower differ from the value used here?
Yes. Electrical horsepower is defined as exactly 746 W, while this converter uses mechanical horsepower at 745.6999 W. The difference is tiny, about 0.04 percent, so they are interchangeable for most purposes.
How do I convert watts back to horsepower?
Divide the watts by 745.6999, or multiply by 0.001341022. For example, 1,000 W equals about 1.341 hp.
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