Force Calculator
How this force calculator works
Choose what to solve for — force, mass, or acceleration — then enter the other two values. The calculator converts all inputs to SI base units (newtons, kilograms, and m/s²) before applying Newton’s second law, then converts the result back to the display unit you selected.
The force formula (Newton’s second law)
F = m × a (force = mass × acceleration)
m = F / a (mass = force ÷ acceleration)
a = F / m (acceleration = force ÷ mass)
Force unit reference
- 1 N = 1 kg·m/s² (SI base unit)
- 1 lbf = 4.44822 N (pound-force)
- 1 kgf = 9.80665 N (kilogram-force)
- 1 dyne = 10⁻⁵ N (CGS unit)
FAQ
What is Newton’s second law of motion?
Newton’s second law states that the net force acting on an object equals the product
of its mass and acceleration (F = m × a). It describes how the velocity of an object
changes when an external force is applied, with acceleration directly proportional to force
and inversely proportional to mass.
What are the SI units of force?
The SI unit of force is the newton (N), defined as the force required to accelerate a 1 kg
mass at 1 m/s² (1 N = 1 kg·m/s²). Related units include the dyne
(1 N = 10⁵ dyne) in the CGS system and the kilogram-force (1 kgf = 9.80665 N).
How do I convert between force units?
Common conversions: 1 N = 0.224809 lbf (pound-force), 1 lbf = 4.44822 N, 1 N = 10⁵ dyne,
1 kgf = 9.80665 N, 1 kip = 4448.22 N. To convert from newtons, multiply by the conversion
factor; to convert to newtons, divide by it.