Horsepower Calculator

Understanding Horsepower Calculator

Horsepower is a unit of power. 1 mechanical horsepower = 745.7 watts. Originally defined by James Watt to compare steam engines to horses.

How to use this calculator

1. Enter a value in horsepower if you want the equivalent in watts, or enter watts if you want horsepower.
2. Check that you are using the correct direction of conversion before reading the result.
3. Use the displayed formula, where \(1 \text{ HP} = 745.7 \text{ W}\), to understand how the conversion is done.
4. Review the example to see how the calculator turns one unit into the other.

The formula explained

The formula \(1 \text{ HP} = 745.7 \text{ W}\) means that one horsepower is equal to 745.7 watts. To convert horsepower to watts, multiply by 745.7, and to convert watts to horsepower, divide by 745.7.

• HP = horsepower, a unit of power
• W = watts, a unit of power
• x = the given power value you want to convert

Step by step method

1. If you start with horsepower, multiply the number of HP by \(745.7\) to get watts.
2. If you start with watts, divide the number of W by \(745.7\) to get horsepower.
3. Keep the units in your work so you can see whether you are converting from HP to W or from W to HP.

Worked example

Problem. Convert \(3\) HP to watts.

1. Start with the formula \(1 \text{ HP} = 745.7 \text{ W}\).
2. Multiply \(3\) by \(745.7\): \(3 \times 745.7 = 2237.1\).
3. So, \(3\) HP equals \(2237.1\) W.

Tips and common mistakes

• Make sure you do not divide when converting from HP to W, because that will give the wrong unit.
• If your result seems too large or too small, check whether you entered the value in the correct unit.

Frequently asked questions