Watt to Horsepower Calculator
Convert power between watts and horsepower instantly. Supports mechanical, metric, and electrical horsepower conversions. Perfect for automotive, engineering, and electrical applications.
What Is Horsepower?
Horsepower (HP) is a unit of power that measures the rate at which work is done. It was originally defined by James Watt in the 18th century to compare the output of steam engines to the power of draft horses. Today, horsepower is used primarily in the automotive and machinery industries to rate engine power.
There are several different types of horsepower:
- Mechanical HP (Imperial HP): 1 HP = 550 ft·lb/s = 745.699872 W
- Metric HP (PS): 1 HP = 75 kgf·m/s = 735.49875 W
- Electrical HP: 1 HP = 746 W (exact)
The watt (W) is the SI unit of power. It is defined as 1 joule per second. One watt is a relatively small unit, so kilowatts (kW) are often used for larger power values.
How Does the Watt to Horsepower Calculator Work?
The calculator uses the following conversion factors:
Mechanical HP: 1 HP = 745.699872 W
Metric HP (PS): 1 HP = 735.49875 W
Electrical HP: 1 HP = 746 W
For conversion:
W → HP: HP = W ÷ Conversion Factor
HP → W: W = HP × Conversion Factor
Simply enter a value in either unit, select the direction of conversion, and choose the type of horsepower. The calculator will instantly compute the equivalent power value.
Why Use This Watt to Horsepower Calculator?
- Two-Way Conversion: Convert from watts to horsepower and from horsepower to watts.
- Multiple HP Types: Supports mechanical, metric, and electrical horsepower.
- Precise Results: Uses exact conversion factors for each horsepower type.
- Scientific Notation: Display large numbers in standard or scientific format.
- Free & Private: No registration, no data storage.
Common Power Equivalents
- 1 Mechanical HP = 745.7 W = 0.7457 kW
- 1 Metric HP = 735.5 W = 0.7355 kW
- 1 Electrical HP = 746 W = 0.746 kW
- 1 kW = 1.341 Mechanical HP = 1.360 Metric HP = 1.340 Electrical HP
❓ Watt to Horsepower FAQ
What is horsepower?
Horsepower is a unit of power that measures the rate at which work is done. It was defined by James Watt to compare steam engine output to draft horses.
How many watts are in 1 mechanical horsepower?
1 mechanical horsepower (HP) equals 745.699872 watts.
How many watts are in 1 metric horsepower?
1 metric horsepower (PS) equals 735.49875 watts.
How many watts are in 1 electrical horsepower?
1 electrical horsepower equals exactly 746 watts.
What is the difference between mechanical and metric horsepower?
Mechanical horsepower (Imperial HP) is based on 550 ft·lb/s and equals 745.7 W. Metric horsepower (PS or CV) is based on 75 kgf·m/s and equals 735.5 W. Metric horsepower is slightly smaller than mechanical horsepower.
What is electrical horsepower?
Electrical horsepower is used for electric motors and is defined as exactly 746 watts. It is a standard rating for electric motor power.
How do I convert watts to mechanical horsepower?
Divide the number of watts by 745.699872. For example: 1000 W ÷ 745.699872 = 1.341 HP.
How do I convert mechanical horsepower to watts?
Multiply the number of horsepower by 745.699872. For example: 1 HP × 745.699872 = 745.70 W.
What is the difference between horsepower and kilowatts?
Horsepower and kilowatts are both units of power. 1 kW = 1000 W. 1 mechanical HP = 0.7457 kW. 1 metric HP = 0.7355 kW. 1 electrical HP = 0.746 kW.
Why are there different types of horsepower?
Different standards evolved over time in different countries and industries. Mechanical HP is used in the US and UK, metric HP (PS) is used in Europe, and electrical HP is used for electric motors.
How do I convert watts to kilowatts?
Divide watts by 1000. For example: 746 W ÷ 1000 = 0.746 kW.
What is the power of a typical car engine in horsepower?
A typical car engine produces 100-300 mechanical horsepower (75-225 kW). High-performance cars can produce over 500 HP (370 kW).
How many horsepower is 1 kW?
1 kW equals 1.341 mechanical HP, 1.360 metric HP, or 1.340 electrical HP.
What is the formula for converting watts to horsepower?
For mechanical HP: HP = W ÷ 745.699872. For metric HP: HP = W ÷ 735.49875. For electrical HP: HP = W ÷ 746.
How do I convert BTU to horsepower?
1 mechanical HP = 2,545 BTU per hour. To convert BTU/h to HP, divide by 2,545. To convert HP to BTU/h, multiply by 2,545.
What is the difference between power and energy?
Power is the rate at which energy is used or produced, measured in watts or horsepower. Energy is the total amount of work done, measured in joules or kilowatt-hours. Power = Energy ÷ Time.
Can I use this calculator for engine power ratings?
Yes. This calculator is ideal for converting engine power ratings between watts and horsepower, which is useful for comparing engines with different rating systems.