Force Calculator (F = ma)
Calculate force from mass and acceleration using Newton’s second law, with the result in newtons, kilogram-force and pounds-force.
How it works
F = m · a
Newton’s second law says the net force on an object equals its mass times its acceleration. The larger the mass, the more force it takes to produce the same change in motion, and the harder you push, the faster it accelerates. Force is measured in newtons, where one newton accelerates one kilogram at one metre per second squared.
Worked example
A net force on a 10 kg mass giving 2 m/s² of acceleration is F = 10 × 2 = 20 N (about 2.04 kgf or 4.50 lbf).
Sources: Newton’s laws of motion — Wikipedia
Frequently asked questions
What is one newton?
One newton is the force that accelerates a 1 kg mass at 1 m/s². For scale, holding a small apple against gravity takes roughly one newton.
Is this the net force or a single force?
F = ma always gives the net (resultant) force — the vector sum of every force acting. If other forces such as friction are present, the applied force must be larger to leave this much left over for acceleration.
How is force different from weight?
Weight is a specific force: mass times gravitational acceleration (about 9.81 m/s² on Earth). This calculator uses whatever acceleration you enter, so it works for any push, not just gravity.
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Educational estimate. Check the formula and units for your exact case.