Watts to Horsepower Converter

Convert watts to mechanical horsepower instantly, with a reference table covering engines, motors and appliances.

Watts

Horsepower

1 W = 0.0013 hp

Multiply watts by 0.00134102 to get horsepower.

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.

Watts to horsepower reference table

The conversions people look up most often, rounded to 4 decimal places.

Common watts to horsepower conversions
Watt (W)	Horsepower (hp)
100 W	0.1341 hp
746 W	1.0004 hp
1,000 W	1.341 hp
5,000 W	6.7051 hp
10,000 W	13.4102 hp
50,000 W	67.0511 hp
75,000 W	100.5767 hp
100,000 W	134.1022 hp
150,000 W	201.1533 hp
200,000 W	268.2044 hp
500,000 W	670.511 hp

The watts people look up most

100 W = 0.1341 hp: About what a fit person can sustain on a bicycle for an hour.
746 W = 1.0004 hp: Exactly one mechanical horsepower. James Watt set the figure himself, from what a mill horse could lift.
1,000 W = 1.341 hp: A kilowatt, 1.341 hp. Electric motors are rated in kilowatts almost everywhere except the United States.
3,000 W = 4.0231 hp: A common generator and inverter rating, where the horsepower figure is rarely printed at all.
5,000 W = 6.7051 hp: Small generator and pressure-washer territory, sold in watts in Europe and horsepower in America.
100,000 W = 134.1022 hp: A mid-size car engine, and why electric cars quoting kilowatts sound less powerful than they are.

How the watts to horsepower calculation works

One mechanical horsepower is 745.7 watts:

horsepower = watts ÷ 745.69987

There is more than one horsepower, and the differences are small but real:

Type	Watts	Used for
Mechanical (imperial)	745.70	US and UK engine ratings
Metric (PS, CV)	735.50	European car specifications
Electrical	746	Motor nameplates
Boiler	9,809.5	Steam plant

This converter uses mechanical horsepower. A European car rated 150 PS is 110.3 kW, which is 147.9 mechanical hp — the 2% gap is why the same car is quoted with slightly different figures in different markets.

James Watt derived the unit in the 1780s from the rate at which a dray horse could raise coal, deliberately choosing a generous figure so his steam engines would not be oversold against the animals they replaced.

Everyday ratings:

A kettle, 3,000 W → 4.02 hp
A vacuum cleaner, 1,400 W → 1.88 hp
A small EV motor, 80,000 W → 107.3 hp
A Tesla Model 3 Performance, 377,000 W → 505.6 hp
A family car, 110,000 W → 147.5 hp

Electric vehicles are rated in kilowatts almost everywhere, which is why EV power figures feel unfamiliar: 100 kW is 134 hp, and 200 kW is 268 hp. A quick rule is that kilowatts × 4/3 gives horsepower.

A sustained human output is about 100 W — roughly 0.13 hp — which is a fair measure of how much work an engine replaces.

Frequently asked questions

What is the difference between a kilowatt and a kilowatt-hour?

One is a rate and the other a quantity. A kilowatt is power - how fast energy is being used - and a kilowatt-hour is the energy a kilowatt uses in an hour. Horsepower is a rate too, so it converts to kilowatts but never to kilowatt-hours. A 1.34 hp motor is a 1 kW motor, and running it for three hours consumes 3 kWh.

How much power can a domestic socket deliver?

A British 13 A socket on a 230 V supply manages about 3,000 W, which is 4.0 hp. An American 15 A socket at 120 V manages 1,800 W, or 2.4 hp, which is why US workshop machines above roughly 2 hp are wired to a 240 V circuit instead. The same tool therefore carries different ratings in the two markets without anything changing inside the motor.

Why is a horsepower figure always quoted with an rpm?

Because power is torque multiplied by rotational speed. An engine making 200 Nm at 3,000 rpm produces 62.8 kW, or 84.2 hp; the same torque at 6,000 rpm would be twice the power. That is why a peak power figure is meaningless without the engine speed it occurs at, and why an electric motor with flat torque from zero makes its peak well up the range.

Watts to Horsepower Converter