Gravitational Force Calculator
Enter two masses and the distance between their centres to find the force of attraction.
This result is an estimate only. Double-check important figures before relying on them.
How it is calculated
- F = G × m₁ × m₂ ÷ r²
- G = 6.6743 × 10⁻¹¹ N·m²/kg²
- Acceleration of a mass = F ÷ that mass
For everyday force problems, use the force calculator.
Worked example
Earth (5.972 × 10²⁴ kg) and the Moon (7.348 × 10²² kg), 384,400 km apart:
Why your number may differ
The formula treats the bodies as points, or as uniform spheres measured from their centres. Real distances and masses are rounded.
Frequently asked questions
What is the formula for gravitational force?
F = G × m₁ × m₂ ÷ r², where G = 6.6743 × 10⁻¹¹ N·m²/kg² and r is the distance between the centres of the masses.
What happens when the distance doubles?
The force falls to a quarter, because it depends on the square of the distance.
Why are the defaults the Earth and the Moon?
They give a recognisable large-scale result of about 1.98 × 10²⁰ newtons, which keeps the Moon in orbit.