Physics
Force Calculator
Apply Newton’s second law by entering mass and acceleration to get force in newtons or pounds-force.
forcenewtonmass
Force (F = m·a)
Compute force from mass and acceleration using Newton’s second law.
Force
42 N
Kilonewtons
0.042 kN
Pound-force
9.442 lbf
Newton's second law
Force = Mass × Acceleration
Mass may be in kilograms or pounds (converted internally). Acceleration accepts m/s² or ft/s² so the resulting force matches the unit system.
How to use
- Choose your preferred mass and acceleration units.
- Enter the values with appropriate signs to indicate direction if desired.
- Read the force in newtons, pound-force, and kilonewtons.
Example
Input: Mass = 12 kg, Acceleration = 3.5 m/s²
Output: Force ≈ 42.0 N, ≈ 9.45 lbf
FAQ & notes
How do I work with gravity?
Enter 9.81 m/s² (or 32.17 ft/s²) as the acceleration to approximate the force due to Earth's gravity.
Can I solve for mass or acceleration instead?
Use the speed/distance/time layout as a template; this calculator currently solves only for force.