What is the difference between power and energy?

Energy is the total work done (joules). Power is the rate at which energy is used or transferred (watts = joules per second). A 100W bulb uses 100 joules every second.

How many watts is 1 horsepower?

1 horsepower (hp) = 745.7 watts. So a 200 hp car engine produces about 149,140 watts (149 kW) at peak.

Power Calculator (Physics)

Quick answer: Enter work and time, or force and velocity, to calculate power in watts, kW, and horsepower.

Calculate mechanical power using either P = W/t (work divided by time) or P = F×v (force times velocity). Results in watts, kilowatts, and horsepower.

Last reviewed: April 2026Report an error

Method

Work / TimeForce × Velocity

Work (J)

Time (s)

Power

100.00 W

Power: 100.00 W (0.1000 kW, 0.1341 hp).

Watts

100.00

Kilowatts

0.1000

Horsepower

0.1341

How to Use This Power (Physics) Calculator

1Enter work (joules) and time (seconds) — OR — force (newtons) and velocity (m/s).
2Read power in watts, kilowatts, and horsepower.

Frequently Asked Questions

: Energy is the total work done (joules). Power is the rate at which energy is used or transferred (watts = joules per second). A 100W bulb uses 100 joules every second.
: 1 horsepower (hp) = 745.7 watts. So a 200 hp car engine produces about 149,140 watts (149 kW) at peak.

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Power Calculator (Physics)

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Frequently Asked Questions

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