Watts to Horsepower Conversion Calculator

Watts to Horsepower Calculator

Enter power in watts:

Mechanical horsepower result: hp(I)

Electrical horsepower result: hp(E)

Metric horsepower result: hp(M)

A Watts to Horsepower calculator converts power measurements between the SI unit (watts) and the mechanical/imperial unit (horsepower). This conversion is essential for:

✅ Automotive engineering (engine power ratings)
✅ Industrial machinery (motor specifications)
✅ HVAC systems (compressor power)
✅ Electric motor applications

Key Definitions

• Watt (W): SI unit of power (1 W = 1 joule/second)
• Horsepower (HP): Mechanical power unit (1 HP ≈ 745.7 W)

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Conversion Formulas

1. Watts to Mechanical Horsepower

$$P(HP)=\frac{P(W)}{745.7}$$

Example:
Convert 2,000 W to HP:

$$2,000÷745.7\approx 2.68\text{ HP}$$

2. Horsepower to Watts

$$P(W)=P(HP)\times 745.7$$

Example:
Convert 5 HP to W:

$$5\times 745.7=3,728.5\text{ W}$$

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Conversion Table (W ⇆ HP)

Watts (W)	Mechanical HP	Typical Application
745.7 W	1 HP	Small engine
1,000 W	1.34 HP	Electric scooter
1,500 W	2.01 HP	Residential water pump
3,000 W	4.02 HP	Commercial tools
7,457 W	10 HP	Industrial motors
14,914 W	20 HP	Automotive applications
74,570 W	100 HP	Performance car engines

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How to Use the Calculator

1. Enter Watts → Get HP (Divide by 745.7)

2. Enter HP → Get Watts (Multiply by 745.7)

Example Calculations:

• 3,500 W to HP:

$$3,500÷745.7\approx 4.69\text{ HP}$$

• 7.5 HP to W:

$$7.5\times 745.7=5,592.75\text{ W}$$

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Practical Applications

• Car Engines: 150 HP = 111,855 W
• Air Conditioners: 1.5 HP = 1,118.55 W
• Industrial Pumps: 20 HP = 14,914 W

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Comparison of Power Units

Unit	Watts Equivalent	Horsepower Equivalent
1 W	1 W	0.00134 HP
1 HP (mechanical)	745.7 W	1 HP
1 HP (metric)	735.5 W	0.986 HP

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FAQ

1. How many HP is 1,000 W?

✅ 1,000 W ≈ 1.34 HP

2. Why do cars use HP instead of watts?

🔹 Historical convention from steam engine days
🔹 More intuitive for mechanical power ratings

3. Is HP or kW more accurate?

🔹 Watts/kW are SI units - preferred for technical precision
🔹 HP remains standard in automotive/mechanical industries

4. How to convert 5,000 W to HP?

$$5,000÷745.7\approx 6.7\text{ HP}$$

5. What's the difference between HP and PS?

🔹 1 HP (mechanical) = 745.7 W
🔹 1 PS (metric) = 735.5 W