Force Calculator (F = ma)
Calculate force, mass, or acceleration using Newton's second law: F = m × a.
What is Force Calculator (F = ma)?
The force calculator applies Newton's second law: F = ma. Force in newtons (N) equals mass (kg) times acceleration (m/s²).
Formula
F = m × a. 1 newton = the force needed to accelerate a 1 kg mass at 1 m/s².
Worked example
10 kg × 5 m/s² = 50 N. About 11.2 lbf — the force required to push a 10 kg cart at 5 m/s² acceleration.
How to use this calculator
- Enter mass and acceleration.
- Force in newtons, pound-force, and dyne appears.
Frequently asked questions
What is a newton?
A newton (N) is the SI unit of force. 1 N is the force needed to accelerate 1 kg at 1 m/s². Equivalent to about 0.225 pounds-force or the weight of a 100g chocolate bar on Earth.
How does weight relate to force?
Weight is the gravitational force on an object. On Earth, weight (in N) = mass (in kg) × 9.81 m/s². So a 100 kg person weighs 981 N.
What about friction?
F = ma gives the net force. To move an object, you must also overcome friction. Net force = applied force − friction.
Why is this called Newton's second law?
It's the second of three laws Newton published in 1687. The first is inertia (objects at rest stay at rest). The second is F = ma. The third is action and reaction (forces come in pairs).