Convert Horsepower to Watts
Instantly convert Horsepower (hp) to Watts (W) with our free online calculator.
Formula: hp to W — multiply by 745.7
Reference Table
| Horsepower (hp) | Watts (W) |
|---|---|
| 1 | 745.7 |
| 5 | 3728.5 |
| 10 | 7457 |
| 25 | 18642.5 |
| 50 | 37285 |
| 100 | 74570 |
How to Convert Horsepower to Watts
Formula
To convert Horsepower (hp) to Watts (W): multiply by 745.7
Step-by-Step
- Start with your value in Horsepower (hp).
- Multiply by 745.7 to perform the conversion.
- The result is your value expressed in Watts (W).
Conversion Factor
1 hp = 745.7 W
Reverse Factor
1 W = 0.00134102 hp
Worked Example
Convert 25 Horsepower to Watts: 25 hp = 18642.5 W
About Horsepower (hp)
An imperial unit of power equal to approximately 745.7 watts (mechanical horsepower per NIST SP 811: 1 hp = 33,000 ft·lbf/min exactly = 550 ft·lbf/s = 745.69987158227022 W). Originally defined by James Watt in the 1780s by measuring how much coal a typical pit-pony could lift from a Cornish coal mine, then scaled up to match draft-horse-team output for marketing his steam engines. Horsepower remains the dominant US power unit for: passenger-car engines (a typical sedan 150-300 hp; full-size pickup 350-450 hp; Tesla Model S Plaid 1,020 hp; Bugatti Chiron Super Sport 1,578 hp), outboard motors (Mercury Verado 600 hp), agricultural tractors (John Deere 8R 410 hp), riding lawn equipment, residential HVAC blower motors, RV gen-sets, marine inboards, and industrial electric motors per NEMA MG-1 ratings. **Important**: 'Metric horsepower' or PS / CV (Pferdestärke / Cheval Vapeur) is slightly different at exactly 735.49875 W per 1985 EU directive — a detail that matters when comparing US-spec vs European-spec engine ratings (German auto-magazine '500 PS' is ~493 US hp). Convert hp to kW by multiplying by 0.7457; to BTU/hr by multiplying by 2,544.
About Watt (W)
The SI unit of power (ISO 80000-5 §5-19), defined as exactly one joule per second (1 W = 1 J/s = 1 kg·m²/s³ = 1 V·A in electrical systems). Named after Scottish mechanical engineer James Watt (1736-1819), whose late-18th-century improvements to the Newcomen atmospheric steam engine (separate condenser, sun-and-planet gear) launched the Industrial Revolution and made power-unit standardization economically necessary. The watt is the universal electrical and mechanical power unit across scientific publication, engineering, consumer electronics, and energy markets. Reference values: a typical 9 W LED bulb produces ~800 lumens (equivalent to a 60 W incandescent at 14 lm/W luminous efficacy); audio equipment output power (a hi-fi home amplifier 50-200 W per channel; a concert PA system 5,000-50,000 W); a modern crystalline-silicon residential solar PV module ~350-450 W peak per panel under STC; a household refrigerator continuous load ~150 W average; a high-end gaming PC at full load ~700 W; a Tesla Model S Plaid peak motor output ~760 kW (1,020 hp); the world's electricity-generating capacity ~8 TW (8 × 10¹² W).
Quick Facts
- 1 Horsepower equals 745.7 Watts
- 1 Watt equals 0.00134102 Horsepower
- Horsepower is a unit of power
- Watt is a unit of power
- This conversion is commonly used in electrical systems, automotive performance, and HVAC sizing
- The Horsepower belongs to the imperial system
- The Watt belongs to the metric system
Common Horsepower to Watt Conversions
| Horsepower (hp) | Watts (W) |
|---|---|
| 0.01 | 7.457 |
| 0.1 | 74.57 |
| 0.25 | 186.425 |
| 0.5 | 372.85 |
| 1 | 745.7 |
| 2 | 1491.4 |
| 3 | 2237.1 |
| 5 | 3728.5 |
| 10 | 7457 |
| 15 | 11185.5 |
| 20 | 14914 |
| 25 | 18642.5 |
| 50 | 37285 |
| 75 | 55927.5 |
| 100 | 74570 |
| 250 | 186425 |
| 500 | 372850 |
| 1000 | 745700 |
| 5000 | 3728500 |
| 10000 | 7457000 |
Understanding Horsepower
The Horsepower (symbol: hp) is a unit of power. An imperial unit of power equal to approximately 745.7 watts (mechanical horsepower per NIST SP 811: 1 hp = 33,000 ft·lbf/min exactly = 550 ft·lbf/s = 745.69987158227022 W). Originally defined by James Watt in the 1780s by measuring how much coal a typical pit-pony could lift from a Cornish coal mine, then scaled up to match draft-horse-team output for marketing his steam engines. Horsepower remains the dominant US power unit for: passenger-car engines (a typical sedan 150-300 hp; full-size pickup 350-450 hp; Tesla Model S Plaid 1,020 hp; Bugatti Chiron Super Sport 1,578 hp), outboard motors (Mercury Verado 600 hp), agricultural tractors (John Deere 8R 410 hp), riding lawn equipment, residential HVAC blower motors, RV gen-sets, marine inboards, and industrial electric motors per NEMA MG-1 ratings. **Important**: 'Metric horsepower' or PS / CV (Pferdestärke / Cheval Vapeur) is slightly different at exactly 735.49875 W per 1985 EU directive — a detail that matters when comparing US-spec vs European-spec engine ratings (German auto-magazine '500 PS' is ~493 US hp). Convert hp to kW by multiplying by 0.7457; to BTU/hr by multiplying by 2,544.
It belongs to the imperial measurement system.
Horsepower are commonly used in electrical systems, automotive performance, and HVAC sizing.
Understanding Watts
The Watt (symbol: W) is a unit of power. The SI unit of power (ISO 80000-5 §5-19), defined as exactly one joule per second (1 W = 1 J/s = 1 kg·m²/s³ = 1 V·A in electrical systems). Named after Scottish mechanical engineer James Watt (1736-1819), whose late-18th-century improvements to the Newcomen atmospheric steam engine (separate condenser, sun-and-planet gear) launched the Industrial Revolution and made power-unit standardization economically necessary. The watt is the universal electrical and mechanical power unit across scientific publication, engineering, consumer electronics, and energy markets. Reference values: a typical 9 W LED bulb produces ~800 lumens (equivalent to a 60 W incandescent at 14 lm/W luminous efficacy); audio equipment output power (a hi-fi home amplifier 50-200 W per channel; a concert PA system 5,000-50,000 W); a modern crystalline-silicon residential solar PV module ~350-450 W peak per panel under STC; a household refrigerator continuous load ~150 W average; a high-end gaming PC at full load ~700 W; a Tesla Model S Plaid peak motor output ~760 kW (1,020 hp); the world's electricity-generating capacity ~8 TW (8 × 10¹² W).
It belongs to the metric measurement system.
Watts are commonly used in electrical systems, automotive performance, and HVAC sizing.
Why Convert Horsepower to Watts?
Power conversions between Horsepower and Watts are needed in electrical engineering, automotive performance comparison, and HVAC system design. Motor ratings, generator capacities, and appliance specifications are published in different power units depending on the manufacturer and region.
Frequently Asked Questions
How do I convert Horsepower to Watts?
An imperial unit of power equal to approximately 745. To convert Horsepower to Watts, multiply by 745.7. For example, 25 hp equals 18642.5 W.
How many Watts are in 1 Horsepower?
There are 745.7 Watts in 1 Horsepower.
How many Horsepower are in 1 Watt?
There are 0.00134102 Horsepower in 1 Watt.
What is the formula for Horsepower to Watt conversion?
The formula is: multiply by 745.7. This means 1 hp = 745.7 W.
Is a Horsepower bigger than a Watt?
No. One Horsepower is smaller than one Watt because 1 hp equals 745.7 W, which is greater than 1.
When do you need to convert between Horsepower and Watts?
The SI unit of power (ISO 80000-5 §5-19), defined as exactly one joule per second (1 W = 1 J/s = 1 kg·m²/s³ = 1 V·A in electrical systems). Horsepower and Watt are both power units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.