Horsepower to watts

Multiply horsepower by 745.6999 to get watts.

1 hp = 745.6999 WNIST SP 811

Convert

7,456.9987W

10 hp = 7,456.9987 W

How to convert horsepower to watts

The watt is the SI unit of power, one joule per second. The horsepower is mechanical (imperial) horsepower, about 745.70 watts.

Worked example — 10 hp: 10 × 745.6999 = 7,456.9987 W.

Horsepower to watts table

Common conversions. The reverse table is on watts to horsepower.
Horsepower	Watts
0.5 hp	372.8499 W
1 hp	745.6999 W
2 hp	1,491.3997 W
5 hp	3,728.4994 W
10 hp	7,456.9987 W
50 hp	37,284.9936 W
100 hp	74,569.9872 W
200 hp	149,139.9743 W
500 hp	372,849.9358 W

Reverse and related

watts → horsepowerreverse conversion kW → hp1 kW = 1.341 hp hp → kW1 hp = 0.7457 kW kW → W1 kW = 1,000 W hp → PS1 hp = 1.0139 PS W → kW1 W = 0.001 kW BTU/h → kW1 BTU/h = 0.000293071 kW

About horsepower and watts

Horsepower (hp)

1 hp = 745.6999 W

Definition. Mechanical (imperial) horsepower, about 745.70 watts

History and origin

Horsepower was coined by James Watt in the 1780s to compare his steam engines to the draught horses they replaced, based on the work a horse could do. Mechanical horsepower is about 745.7 watts.

Current use

Horsepower rates car and engine power in the United States and United Kingdom.

Source: NIST SP 811, App. B (power). Mechanical hp = 550 ft·lbf/s ≈ 745.70 W; metric hp (PS) = 75 kgf·m/s = 735.49875 W

Watt (W)

1 W = 0.00134102 hp

Definition. The SI unit of power, one joule per second

History and origin

The watt is the SI unit of power, one joule per second, named after James Watt for his work on the steam engine. It measures the rate at which energy is used or produced.

Current use

Watts rate light bulbs, appliances and solar panels the world over.

Source: NIST SP 811, App. B (power). Mechanical hp = 550 ft·lbf/s ≈ 745.70 W; metric hp (PS) = 75 kgf·m/s = 735.49875 W

Where people use this

Horsepower: car and engine power in the US/UK. Watts: light bulbs, appliances, solar panels. 1 hp is about 745.7 W.

How we know this is right

The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:

1 W = 0.00134102209 hp, so 1 hp = 1 ÷ 0.00134102209 = 745.6999 W.

Every value is carried to full double precision; the display is rounded.

Both units are defined in NIST SP 811, App. B (power). Mechanical hp = 550 ft·lbf/s ≈ 745.70 W; metric hp (PS) = 75 kgf·m/s = 735.49875 W.

Questions people ask

How many watts is 1 hp?

One horsepower is about 745.7 watts.

How many watts is 2 hp?

2 hp is about 1491 watts.

How many hp is 1000 W?

1000 W is about 1.34 hp.

All horsepower conversions

Horsepower to kilowatts1 hp = 0.7457 kW Kilowatts to horsepower1 kW = 1.341 hp Watts to horsepower1 W = 0.00134102 hp Horsepower to metric horsepower1 hp = 1.0139 PS