Acceleration from Force Calculator
Calculate acceleration, force, or mass using Newton's Second Law (F=ma).
Enter any two values to solve for the third, with SI and imperial unit options.
Newton’s Second Law of Motion is one of the most fundamental equations in all of physics:
F = m × a
Where:
- F = Force, measured in Newtons (N), 1 Newton = 1 kg·m/s²
- m = Mass, measured in kilograms (kg)
- a = Acceleration, measured in meters per second squared (m/s²)
This law states that the net force on an object equals its mass multiplied by its acceleration. Equivalently:
- a = F / m: acceleration equals force divided by mass
- m = F / a: mass equals force divided by acceleration
Understanding each variable:
Force (F): A push or pull on an object. Forces include gravity (weight), friction, tension, thrust, and normal force. The unit is the Newton — approximately the force needed to accelerate 1 kg by 1 m/s² (or roughly the weight of an apple).
Mass (m): A measure of how much matter an object contains. Mass is NOT the same as weight. Mass is the same everywhere; weight depends on local gravity. On the Moon (g ≈ 1.62 m/s²), your mass is unchanged but your weight is 1/6 of Earth’s.
Acceleration (a): The rate of change of velocity. Positive acceleration means speeding up; negative acceleration (deceleration) means slowing down. Earth’s gravitational acceleration is 9.81 m/s².
Practical examples:
- A 1,000 kg car accelerating at 3 m/s² requires: F = 1000 × 3 = 3,000 N of net force
- A 70 kg person falling freely accelerates at 9.81 m/s² due to: F = 70 × 9.81 = 686.7 N (their weight)
- A rocket producing 1,000 N of thrust pushing a 200 kg payload: a = 1000 / 200 = 5 m/s²
Unit conversion reference:
- 1 kN (kilonewton) = 1,000 N
- 1 lbf (pound-force) = 4.448 N
- g (standard gravity) = 9.81 m/s²