Newton's second law says the net force on an object equals its mass times its acceleration, F = ma. Use this force calculator to find any one of force, mass or acceleration from the other two.
Force is in newtons (N). One newton is the force that gives a 1 kg mass an acceleration of 1 m/s². The result is also shown in kilogram-force (kgf), the weight of 1 kg on Earth.
| Find | Force (F) |
| Mass (m) | 25 kg |
| Acceleration (a) | 0.8 m/s² |
| Force (N) | 20 |
| Mass (kg) | 25 |
| Acceleration (m/s²) | 0.8 |
| Force (kgf) | 2.03943 |
A 25 kg trolley accelerating at 0.8 m/s² needs a net force of 20 N.
Try this example →| Find | Acceleration (a) |
| Mass (m) | 1,200 kg |
| Force (F) | 3,000 N |
| Force (N) | 3,000 |
| Mass (kg) | 1,200 |
| Acceleration (m/s²) | 2.5 |
| Force (kgf) | 305.915 |
A 3000 N net force gives a 1200 kg car an acceleration of 2.5 m/s².
Try this example →Force = mass × acceleration (F = ma). The SI unit is the newton (N).
The force that gives a mass of 1 kg an acceleration of 1 m/s². 1 N = 1 kg·m/s².
1 kg has a weight of about 9.81 N on Earth. That is 1 kilogram-force (kgf).
Mass is the amount of matter (kg) and is the same everywhere. Weight is the force of gravity on that mass (N), W = mg.