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Convert hp to W
Convert horsepower (mechanical) (hp) to watt (W) instantly. Free, no signup, nothing is uploaded — everything runs in your browser.
Horsepower (mechanical) to Watt conversion table
| Horsepower (mechanical) [hp] | Watt [W] |
|---|---|
| 0.01 | 7.45699872 |
| 0.1 | 74.56998716 |
| 1 | 745.69987158 |
| 2 | 1,491.39974316 |
| 3 | 2,237.09961475 |
| 5 | 3,728.49935791 |
| 10 | 7,456.99871582 |
| 20 | 14,913.99743165 |
| 50 | 37,284.99357912 |
| 100 | 74,569.98715823 |
| 1,000 | 745,699.8715823 |
How to convert horsepower (mechanical) to watt
W = hp × 745.7
Example: 2 hp = 2 × 745.7 = 1,491.4 W
To convert back (watt to horsepower (mechanical)): hp = W ÷ 745.7
What is a horsepower (mechanical)?
A mechanical horsepower (hp) is a unit of power equal to about 745.7 watts. Standard for engine and motor ratings, especially in the US.
What is a watt?
A watt (W) is the SI unit of power, equal to 1 joule per second.
When do you need to convert horsepower (mechanical) to watt?
Auto and motorcycle specifications list horsepower in the US (a 200 hp engine, a 650 hp supercar), while European and Asian manufacturer specs and EU type-approval documents use kilowatts (the same 200 hp is 149.14 kW). Converting between them is essential when comparing US-market cars to European spec sheets, importing parts, or dealing with EU insurance quotes.
Electric motors and modern EVs are rated in kW (a Tesla Model 3 Long Range is 258 kW ≈ 346 hp), while legacy automotive, marine, and small-engine specs use hp. A boat or lawn mower with a 5 hp engine is 3.73 kW; a 15 hp outboard is 11.18 kW. Marine and small-engine catalogs are still dominantly hp.
Tax and customs forms in many countries require kW for vehicle registration. Importing a US car to the EU requires stating the engine power in kW; the EU driving license categorizes vehicles partly by kW. Off by even 5% here can mean the wrong license category or a failed technical inspection.
Frequently asked questions
What is 1 hp in watts?
1 mechanical horsepower = 745.7 watts, by definition (1 hp = 745.6998715822702 W, exact). The 745.7 figure is the standard rounded value used in most contexts. There is also metric horsepower (PS, CV) = 735.5 W, used in some European contexts; do not confuse the two.
What is 1 hp in kW?
1 hp = 0.7457 kW. So a 100 hp engine is 74.57 kW, a 200 hp engine is 149.14 kW, a 500 hp engine is 372.85 kW. The European Union uses kW on all vehicle documents and driver license categories.
Is mechanical hp the same as metric hp?
No. Mechanical hp (imperial/US) = 745.7 W. Metric hp (PS in Germany, CV in France, CV in Italy) = 735.5 W. The difference is about 1.4%. When converting a European spec sheet, check which "PS" or "CV" refers to. Most modern car sites use kW directly, which sidesteps the ambiguity.
Why is hp 745.7 W and not a round number?
Because 1 hp was originally defined by James Watt as the power a single draft horse could sustain over a full working day. Watt calculated it as 33,000 foot-pounds per minute, which converts to 745.7 W. It is a historical industrial unit, not a clean SI multiple, so the conversion is the slightly awkward 745.7.