Convert Between Watts, Horsepower & Kilowatts Convert between watts, kilowatts, megawatts, horsepower, PS, BTU/h, and ft-lbf/s.

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Power Converter

Convert between watts, kilowatts, megawatts, horsepower, PS, BTU/h, and ft-lbf/s.

Enter power value

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Choose source and target power units.

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What Is Power Converter?

A power converter translates between different units of power — the rate at which energy is transferred or converted. The watt (W) is the SI unit, equal to one joule per second. Mechanical horsepower (hp), defined by James Watt as 550 ft·lbf/s, is used for engine ratings in the US and UK. Metric horsepower (PS/CV/pk) equals 735.5 watts and is standard for automotive ratings in Europe and Japan. BTU/h is used for HVAC systems. This converter handles seven power units used across electrical engineering, automotive, and HVAC industries.

Why Use Power Converter?

Covers electrical (W, kW, MW) and mechanical (hp, PS) power units.
Distinguishes between mechanical and metric horsepower.
Essential for automotive, HVAC, and electrical engineering.
Real-time bidirectional conversion.
Reference table for common power values.

Common Use Cases

Automotive

Compare engine power ratings between hp, PS, and kW.

HVAC

Convert between BTU/h and watts for heating/cooling system sizing.

Electrical Engineering

Switch between watts, kilowatts, and megawatts when designing power systems.

Industrial

Match motor and generator power ratings across regional standards.

Technical Guide

Power is the rate of energy transfer: P = E/t.

• 1 kW = 1,000 W
• 1 MW = 1,000,000 W
• 1 hp (mechanical) = 550 ft·lbf/s = 745.7 W
• 1 PS (metric hp) = 75 kgf·m/s = 735.499 W
• 1 BTU/h = 0.29307 W
• 1 ft·lbf/s = 1.35582 W

Mechanical horsepower (hp) was defined by James Watt in the 18th century to compare steam engines to horses. Metric horsepower (PS in German, CV in French, pk in Dutch) was later defined as 75 kilogram-force meters per second. The difference between hp and PS is about 1.4%, but it matters for accurate engine specifications.

For electrical systems: watts = volts × amperes (for DC). For AC systems, apparent power in volt-amperes (VA) differs from real power in watts by the power factor.

Tips & Best Practices

1
1 hp ≈ 746 W ≈ 0.746 kW. For quick estimates, divide hp by 1.34 to get kW.
2
Metric horsepower (PS) is about 1.4% less than mechanical horsepower (hp).
3
HVAC: 1 ton of cooling = 12,000 BTU/h ≈ 3,517 W ≈ 3.52 kW.
4
A typical US household uses about 1.2 kW on average (about 900 kWh/month).

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Frequently Asked Questions

Q How many watts is one horsepower?

One mechanical horsepower equals approximately 745.7 watts. One metric horsepower (PS) is about 735.5 watts.

Q What is the difference between hp and PS?

Mechanical horsepower (hp) is 745.7 W, while metric horsepower (PS) is 735.5 W — a difference of about 1.4%. European and Japanese cars use PS; American and British cars use hp.

Q How do I convert kW to hp?

Multiply kW by 1.341 for mechanical horsepower, or by 1.3596 for metric horsepower (PS).

Q What is BTU/h used for?

BTU per hour rates the heating or cooling capacity of HVAC systems, furnaces, and air conditioners.

Q How many BTU/h is one kW?

One kilowatt equals approximately 3,412 BTU/h.

About This Tool

Power Converter is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.