By Zencalcy Editorial TeamLast reviewed About us
Newton's second law ties together the three quantities that describe how a push changes motion: force, mass and acceleration. Enter any two and this calculator returns the third, converting your units to SI first so mixed metric and imperial inputs stay consistent.
Find force, mass or acceleration from Newton's second law.
F = m a
F is the net force in newtons, m is mass in kilograms and a is acceleration in metres per second squared. The force must be the vector sum of every push and pull on the object.
| Symbol | Meaning |
|---|---|
| F | Net force acting on the object, in newtons. |
| m | Mass of the object, in kilograms. |
| a | Acceleration produced by the force, in m/s². |
A 1,200 kg car that accelerates at 3 m/s² needs a net force of 1,200 × 3 = 3,600 N. That is about 810 lbf, roughly what a mid-size engine delivers at the wheels in a brisk overtake.
Continue with the Gravitational Force Calculator, Impact Force Calculator, or the Net Force Calculator — or browse more dynamics tools and all physics calculators.
Yes. Force has a direction, and the acceleration points the same way as the net force. This calculator works with magnitudes, so use the component of the force along the direction of motion.
Results are computed from the standard equations of classical mechanics. Unit conversions use the SI definitions published by NIST. Air resistance is ignored unless the calculator names a drag model.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026