🏋️ Force Calculator
Newton's second law: F = ma
About this calculator
Newton's second law — force equals mass times acceleration (F = m × a) — is the single most used equation in mechanics. Enter any two values and this calculator finds the third: how much force it takes to accelerate a mass, what acceleration a force produces, or the mass behind an observed acceleration. Answers come in newtons, the SI unit of force.
The classic classroom example: a 1,000 kg car accelerating at 3 m/s² needs 3,000 N of force. Watch your units — mass must be in kilograms and acceleration in metres per second squared for the answer to come out in newtons. Practical tip: weight is just mass times gravity (9.81 m/s²), so a 70 kg person "weighs" about 687 N on Earth — force and mass are related but not the same thing.