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🔧 Horsepower to Watt Converter

Convert horsepower to watts and other power units instantly. Supports mechanical, metric (PS), electric, and boiler horsepower types.

📌 Using Mechanical HP (1 hp = 745.7 W)

📋 Common Horsepower to Watt Conversions

Mechanical HPMetric HP (PS)Watts (W)Kilowatts (kW)BTU/hft·lb/s
1 hp1.014 PS745.7 W0.746 kW2,544 BTU/h550 ft·lb/s
5 hp5.069 PS3,728.5 W3.729 kW12,721 BTU/h2,750 ft·lb/s
10 hp10.139 PS7,457 W7.457 kW25,442 BTU/h5,500 ft·lb/s
50 hp50.693 PS37,285 W37.285 kW127,208 BTU/h27,500 ft·lb/s
100 hp101.386 PS74,570 W74.57 kW254,416 BTU/h55,000 ft·lb/s
500 hp506.929 PS372,850 W372.85 kW1,272,080 BTU/h275,000 ft·lb/s

Real-World Horsepower & Power Conversion Examples

🚗 Car Engine Power

A typical mid-size car produces about 200 mechanical HP.

200 HP to Watts: 200 × 745.7 = 149,140 W

200 HP to Kilowatts: 149,140 ÷ 1,000 = 149.14 kW

⚙️ Metric HP (PS) vs Mechanical HP

A European car rated at 150 PS (metric horsepower).

150 PS to Watts: 150 × 735.5 = 110,325 W

150 PS to Mechanical HP: 110,325 ÷ 745.7 = 147.96 hp

🏭 Industrial Boiler Power

A small industrial boiler is rated at 10 boiler HP.

10 Boiler HP to Watts: 10 × 9,809.5 = 98,095 W

10 Boiler HP to kW: 98,095 ÷ 1,000 = 98.1 kW

🏋️ Human vs Machine Power

A trained cyclist can sustain about 0.5 HP (≈ 373 W).

0.5 HP to Watts: 0.5 × 745.7 = 372.85 W

0.5 HP to ft·lb/s: 372.85 × 0.737562 = 275 ft·lb/s

Understanding Horsepower to Watt Conversion

The horsepower (HP) and the watt (W) are both units of power. Horsepower was originally defined by James Watt to compare steam engine output to draft horses. Today, the watt is the SI standard unit of power.

Types of Horsepower

HP TypeAbbreviationEquivalent in Watts
Mechanical HPhp745.7 W
Metric HP (PS)PS735.5 W
Electric HPhpₑ746 W
Boiler HPhp_boiler9,809.5 W
WattW1 W
KilowattkW1,000 W
BTU per HourBTU/h0.293071 W
ft·lb per Secondft·lb/s1.35582 W

Key Conversion Formulas

Watts = HP × 745.7
Mechanical HP to watts
Watts = PS × 735.5
Metric HP to watts
kW = Watts ÷ 1,000
Watts to kilowatts
BTU/h = Watts × 3.41214
Watts to BTU per hour
ft·lb/s = Watts × 0.737562
Watts to foot-pounds per second

How to Convert Step by Step

1
Identify your starting unit — determine whether you have HP (mechanical), PS (metric), electric HP, boiler HP, W, kW, BTU/h, or ft·lb/s.
2
Convert to watts first — use the appropriate conversion factor to express your value in watts, the SI base unit of power.
3
Convert from watts to target unit — use the appropriate formula to get your result in the desired power unit.
4
Verify your result — cross-check against known reference values (e.g., 1 hp = 745.7 W).
🔧
Four HP Types
Convert between mechanical, metric (PS), electric, and boiler horsepower — each with its precise conversion factor.
🎯
High Precision
Accurate conversions using standardized international factors. Results shown to 4 decimal places for engineering precision.
📋
Common Values Table
Quick reference table for common horsepower values (1, 5, 10, 50, 100, 500 HP) converted to all supported power units.
📖
Step-by-Step Guide
Detailed calculation breakdown showing each step of the conversion process with formulas and intermediate values.

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What Is Horsepower?

The horsepower (HP) is a unit of power that measures the rate at which work is done. James Watt defined 1 mechanical HP as 550 foot-pounds per second (745.7 W) to market his steam engines. Today, different definitions exist: mechanical HP (US/UK), metric PS (Europe, ≈ 735.5 W), electric HP (746 W), and boiler HP (≈ 9,809.5 W).

What Is a Watt?

The watt (W) is the SI derived unit of power — one joule per second. It is the universal standard for measuring electrical and mechanical power. Converting between HP and watts bridges traditional engineering units with the modern SI system for precise calculations across automotive, industrial, and scientific applications.

Why Convert Between HP and Watts?

Frequently Asked Questions

How many watts are in 1 horsepower?
One mechanical horsepower (1 hp) = 745.7 watts. Metric HP (1 PS = 735.5 W), electric HP (1 hpₑ = 746 W), boiler HP (1 hp_boiler = 9,809.5 W). Always verify which type you're using.
How do I convert HP to watts manually?
Multiply the HP value by 745.7. Example: 2.5 hp × 745.7 = 1,864.25 W. To convert back, divide by 745.7. For metric HP (PS), use 735.5.
What is the difference between HP and PS?
HP (mechanical) = 745.7 W, PS (metric) = 735.5 W. Difference is about 1.4% — 1 HP ≈ 1.014 PS. PS is used in Germany, France, and other European countries.
How do I convert kW to HP?
Multiply kW by 1.34102 (1 kW ≈ 1.341 hp). Example: 100 kW × 1.34102 = 134.1 hp. To convert HP to kW, multiply by 0.7457.
What is boiler horsepower?
Boiler HP (1 hp_boiler = 9,809.5 W) rates steam boiler capacity — the energy to evaporate 34.5 lb of water/hour at 212°F. It's about 13.15× larger than mechanical HP.

⚠️ Disclaimer: This Horsepower to Watt Converter is for informational purposes only. While we strive for accuracy using standardized conversion factors, verify important power calculations with authoritative sources.