Force, Work and Power Calculator

Mass, kg

Acceleration, m/s²

9.80665 is gravitational acceleration.

Distance, m

Time, s

Result

Force, N98.0665
Work, J196.133
Power, W39.2266
Power, kW0.03923
Horsepower0.05333
Weight on Earth, N98.066

A chain of three formulas

Works out force from mass and acceleration, work from distance and power from time — all three at once.

Three school formulas link into a chain: force is mass times acceleration, work is force times distance, power is work over time. Each builds on the last, which is why calculating them separately is awkward.

The units are named after people and are easily confused. A newton is roughly the force the Earth exerts on a hundred-gram apple. A joule is the work of lifting that apple a metre. A watt is a joule a second — the rate at which work gets done.

What this calculator shows

Force in newtons, work in joules and power in watts
Power in kilowatts and in horsepower
The weight of the mass on Earth

What to keep in mind

Work assumes the force acts along the displacement; at an angle it needs the cosine of that angle.
One metric horsepower is 735.5 watts; the imperial one is slightly larger at 745.7.

FAQs

How do I calculate work in joules?

Multiply force in newtons by distance in metres. Lifting ten kilograms two metres is 196 joules.

How does force differ from weight?

Weight is a particular force: mass times gravitational acceleration. On the Moon the mass is the same and the weight is six times smaller.

How many watts in a horsepower?

735.5 metric, 745.7 imperial. The gap is about one and a half percent, and specifications often confuse the two.

Why is the work zero when holding a weight?

Because nothing moves. Muscles tire and burn energy, but mechanically no work is done.

Worked example

Lifting a load

Input: 10 kg through 2 metres in 5 seconds

Output: Force 98.07 N, work 196.13 J, power 39.23 W

Note: Forty watts is less than a light bulb draws. A person sustains about a hundred watts comfortably and can peak near a thousand, but only for a few seconds.

Useful links

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Force, Work and Power Calculator

Result

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