Convert watts to hp

1. How to convert watts to hp

The conversion is a single multiplication: hp = W × 0.0013410220896. Both units are defined against the same base — the watt (W) — so the factor is fixed and the result is exact to the precision shown.

Worked at the two values people ask for most: 1 W = 0.0013410221 hp and 100 W = 0.13410221 hp. Going the other way, W = hp × 745.699871582, so 1 hp = 745.69987 W.

Results are given to eight significant figures. That is more precision than most jobs need — for a rough figure, treat 1 W as about 0.0013410221 hp and adjust — but rounding early and multiplying afterwards is how a small error becomes a visible one, so the full figure is what the converter carries.

2. Watts to Horsepower conversion table

Every row is the same factor applied — nothing in the table is a special case, and any value in between behaves the same way. Type your own figure into the converter above and the Formula tile shows the arithmetic being used, so the result is checkable rather than taken on trust.

3. What the two units are

• Watts (W). One W is 1 W.
• Horsepower (mechanical) (hp). One hp is 745.69987 W.

Both are converted through the watt (W): the value is multiplied by its own unit's factor to reach the base, then divided by the target unit's factor to leave it. No direct watts to hp factor has to exist or be kept correct, which is also why the converter can show the same value in all 7 power units at once.

Horsepower comes in flavours. Mechanical horsepower is 745.7 W, defined as 550 foot-pounds per second; metric horsepower — PS, the figure in European vehicle specifications — is 735.49875 W, about 1.4% smaller. Both are listed and labelled, because a car quoted at 150 PS is 148 hp, not 150.

If the pair you actually want is not this one, the full unit converter runs every 7 power units off the same factor table, along with 11 other categories of measurement.