Force Calculator

Calculate force, mass or acceleration using Newton's second law. Fill in two of the three fields and leave the third at 0, and the calculator works out the rest.

Force
20
Calculated from mass and acceleration
Mass
10 kg
Acceleration
2 m/s²

How to use the force calculator

  1. Enter the two values you know: mass, acceleration or force.
  2. Leave the field you don't know at 0 — the calculator automatically works it out.
  3. If you fill in all three fields, the calculator instead checks whether they actually agree.

Newton's second law

F = m × a

Newton's second law states that the force (F) acting on an object equals its mass (m) multiplied by the acceleration (a) it undergoes. Force is measured in newtons (N), where 1 N is the force that gives a mass of 1 kg an acceleration of 1 m/s².

If you know two of the three values, you can solve the equation for the third: m = F ÷ a to find mass, or a = F ÷ m to find acceleration.

Frequently asked questions

What is Newton's second law?

Newton's second law describes the relationship between force, mass and acceleration: the force acting on an object equals its mass multiplied by its acceleration (F = m × a). The law is one of the cornerstones of classical mechanics.

What is the unit for force?

Force is measured in newtons (N), named after Isaac Newton. One newton is defined as the force that gives a mass of one kilogram an acceleration of one meter per second squared.

How does gravitational force change with mass?

The gravitational force on an object is proportional to its mass: double the mass and you double the gravitational force too (given the same gravitational acceleration).