Horsepower to Watt Formula
W = hp x 745.7
Conversion factors follow SI relationships published by BIPM and IEC, where those standards apply.
Horsepower to Watt Converter
Quick Answer
1 hp = 745.7 W
Formula: Watt = Horsepower x 745.7
Quick values
Worked examples
Convert 1 hp to W
W = 1 x 745.7
Result: 1 hp = 745.7 W
Convert 10 hp to W
W = 10 x 745.7
Result: 10 hp = 7457 W
Convert 100 hp to W
W = 100 x 745.7
Result: 100 hp = 74570 W
About Horsepower and Watt
This page uses mechanical horsepower from the site library: 1 hp = 745.69987 W (550 ft·lbf/s). Electric horsepower is 746 W even; metric PS is 735.499 W. Pick the definition that matches the nameplate.
Category hub: Power Conversion · Conversion charts · Conversion formulas
Horsepower to Watt Conversion Table
| Horsepower (hp) | Watt (W) |
|---|---|
| 0.25 hp | 186.425 W |
| 0.5 hp | 372.85 W |
| 1 hp | 745.7 W |
| 2 hp | 1491.4 W |
| 5 hp | 3728.5 W |
| 10 hp | 7457 W |
| 25 hp | 18642.5 W |
| 50 hp | 37285 W |
| 100 hp | 74570 W |
Browse all conversion charts → · Browse conversion formulas →
Practical use cases for Horsepower to Watt
Motor and Drive Selection
Nameplates mix horsepower and kilowatts. Specifying a replacement motor requires converting so the electrical supply and mechanical load match.
Generator and Plant Sizing
Prime-mover ratings may be in horsepower while electrical output is in kW or kVA. Planners convert before comparing mechanical and electrical capacity.
HVAC Equipment
Fans, pumps, and chillers are cataloged in horsepower, kW, or tons of refrigeration. Designers convert to the unit used on the project schedule.
Automotive and Marine
Engine output is advertised in horsepower in some markets and kilowatts in others. Comparing vehicles requires a consistent power unit.
Renewable Energy
Inverter and turbine ratings are in kW or MW while some legacy documents still use horsepower. Conversion keeps interconnection studies consistent.
Workshop and Tooling
Machine-tool spindles and air compressors are often labeled in horsepower. Electrical planning converts that rating to kW for feeder and breaker sizing.
Horsepower to Watt FAQs
Common questions about converting horsepower to watt.
How do you convert horsepower to watts?
Multiply mechanical horsepower by 745.700. Example: 1 hp = 745.70 W, 2 hp = 1,491.4 W, 10 hp = 7,457.0 W.
Is 1 hp 746 watts or 745.7 watts?
Electrical horsepower is defined as 746 W. Mechanical (boiler-era) horsepower is 550 ft·lbf/s ≈ 745.70 W. This calculator uses the mechanical unit stored as horsepower.
What is 1.5 hp in watts?
1.5 × 745.700 ≈ 1,118.5 W. Shop vacs and small compressors are often labeled this way.
Where does the horsepower to watt factor come from?
James Watt’s 550 ft·lbf/s definition, converted with the international foot and pound-force. NIST unit tables list the resulting watt value. IEC still prefers the watt on electrical nameplates.
Charts and printable PDF
Use the matching horsepower / watt chart when you need a printable table or offline reference.
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