This force calculator applies Newton's second law to relate mass, acceleration, and force, solving any one from the other two.
Physics
Force Calculator
Calculate force from mass and acceleration with Newton's second law.
Calculator
About this calculator
Formula notes
F = m·a, so a = F / m and m = F / a. Force is in newtons (kg·m/s²).
Worked examples
- Example: a 2 kg mass accelerating at 3 m/s² needs F = 2 × 3 = 6 N.
- Accelerating a 1,200 kg car at 2.5 m/s2 requires a net force of 3,000 N under the simple F = ma model.
How to use it
- Enter the two quantities you know.
- Use kilograms and m/s² for SI newtons.
- Read the missing force, mass, or acceleration.
Frequently asked questions
Is weight a force?
Yes. Weight = m·g with g ≈ 9.81 m/s², so 1 kg weighs about 9.81 N on Earth.
Why is a newton a compound unit?
It is defined through the law itself: 1 N accelerates 1 kg at 1 m/s².
Limits and interpretation
- F = ma describes net force in an inertial frame; individual applied, friction, drag, and gravitational forces must be combined separately.
- Mass must be in compatible units and acceleration should represent the same direction and time interval as the net force.