Horsepower to Watts Converter

Convert horsepower to watts instantly, with a reference table for engines, EV motors and power tools.

Horsepower

Watts

1 hp = 745.7 W

Multiply horsepower by 745.69987158 to get watts.

The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.

Horsepower to watts reference table

The conversions people look up most often, rounded to 2 decimal places.

Common horsepower to watts conversions
Horsepower (hp)	Watt (W)
1 hp	745.7 W
2 hp	1,491.4 W
5 hp	3,728.5 W
10 hp	7,457 W
25 hp	18,642.5 W
50 hp	37,284.99 W
100 hp	74,569.99 W
150 hp	111,854.98 W
200 hp	149,139.97 W
300 hp	223,709.96 W
500 hp	372,849.94 W
700 hp	521,989.91 W
1,000 hp	745,699.87 W

The horsepower people look up most

0.5 hp = 372.85 W: Common for small pumps and workshop extractors, which are labelled in watts outside the US.
1 hp = 745.7 W: Three units share this name: electrical horsepower is defined as exactly 746 W, and metric horsepower as 735.5.
2 hp = 1,491.4 W: Above this the circuit starts to matter: a 13 A UK socket supplies about 3,000 W in total.
5 hp = 3,728.5 W: Typical for a compressor or a small bench machine, and already beyond what one UK socket can supply.
100 hp = 74,569.99 W: A modest car engine, and the figure European specifications lead with - in kilowatts rather than horsepower.
150 hp = 111,854.98 W: This conversion is why the same car is advertised with two very different-looking numbers.

How the horsepower to watts calculation works

One mechanical horsepower is 745.7 watts:

watts = horsepower × 745.69987

For most purposes 1 hp ≈ 0.75 kW, and the reverse rule — kW × 4/3 = hp — is accurate to within half a percent.

Common ratings:

1 hp → 745.7 W
10 hp → 7,457 W (7.46 kW)
150 hp → 111,855 W (111.9 kW) — a typical family car
300 hp → 223,710 W (223.7 kW)
500 hp → 372,850 W (372.9 kW)
1,000 hp → 745,700 W (745.7 kW)

Electric vehicles make this conversion routine, because EV specifications are in kilowatts and the cars they replace were sold in horsepower. A 150 kW motor is 201 hp; a 300 kW dual-motor setup is 402 hp.

Note the difference between motor power and charging power, which share the unit and mean different things. A 250 kW rapid charger delivers energy into the battery; the car's 200 kW motor takes it back out. Both are "250 kW" and "200 kW" but neither figure constrains the other.

Metric horsepower (PS) is 735.5 W, about 1.4% less than mechanical hp. European manufacturers quote PS, so a "200 PS" car is 147.1 kW, or 197.3 mechanical hp. The gap is why the same model appears with two ratings in different markets.

Power tools are quoted inconsistently: a "2 hp" shop vacuum draws about 1,500 W at the wall, which is 2.0 hp of input — the useful output is far lower once motor efficiency is counted. Peak horsepower claims on consumer tools are rarely sustained figures.

Frequently asked questions

What does brake horsepower mean?

It is power measured at the crankshaft on a brake dynamometer, and it is the figure manufacturers quote. Wheel horsepower, measured on a rolling road, is lower by whatever the gearbox and driveline absorb - commonly 10 to 15% on a manual car. Both are mechanical horsepower converting at 745.7 W, so a 150 bhp car putting 128 hp down is 111.9 kW at the crank and 95.5 kW at the tyres.

Why is an outboard motor rated differently from a car engine?

Because it is measured in a different place. Outboards are rated at the propeller shaft under the ICOMIA standard, so a 150 hp outboard delivers that at the prop - 111.9 kW - after the gearcase has taken its share. Car engines are quoted at the crank. Comparing the two ratings directly understates the outboard, which has already paid a transmission loss the car engine has not.

Why are heaters never rated in horsepower?

Because horsepower describes mechanical output and a heater has none. A 2,000 W heater turns all of its electrical input into heat, so calling it 2.68 hp would describe nothing - there is no shaft doing work. The unit stayed with motors, engines and pumps, where the output is movement, which is why air conditioners in parts of Asia are still sized in horsepower.

Horsepower to Watts Converter