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Force Calculator (F = ma)

Calculate force, mass or acceleration with Newton’s second law.

Calculated locally in your browser.

Understanding your result

Use SI units: newtons, kilograms and metres per second squared.

Formula and method

Force = mass × acceleration. So mass = F ÷ a and acceleration = F ÷ m.

Worked example

A 10 kg mass accelerating at 2 m/s² experiences a 20 N force.

How to use this tool

  1. Enter any two values.
  2. Leave the unknown blank.
  3. Press Calculate.

Common mistakes to avoid

  • Using grams instead of kilograms for mass.

About the Force Calculator (F = ma)

Apply Newton’s second law, F = ma, to find force, mass or acceleration from the other two.

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Frequently asked questions

What is one newton?

One newton is the force that accelerates a 1 kg mass at 1 m/s².