Gravitational Force Calculator
Calculate the gravitational attraction between two masses with Newton's law of universal gravitation, F = G·m₁·m₂ / r², using G = 6.674 × 10⁻¹¹ N·m²/kg².
Gravitational force (F = G·m₁·m₂ / r²)
687.367 N
Newton's law of universal gravitation: F = G·m₁·m₂ / r², with G = 6.674 × 10⁻¹¹ N·m²/kg². You can enter values in scientific notation (e.g. 5.972e24). Default values estimate the Earth's pull on a 70 kg person at the surface (≈ 687 N).
Frequently Asked Questions
What is Newton's law of universal gravitation?
Every pair of masses attracts each other with a force F = G·m₁·m₂ / r², where m₁ and m₂ are the masses in kilograms, r is the distance between their centres in metres, and G is the gravitational constant, 6.674 × 10⁻¹¹ N·m²/kg².
How do I calculate the gravitational force between two objects?
Multiply the two masses together, multiply by G, then divide by the square of the distance between their centres. The result is the attractive force in newtons.
What is the gravitational constant G?
G is the universal gravitational constant, approximately 6.674 × 10⁻¹¹ N·m²/kg². It is the same everywhere in the universe and sets the strength of gravity in Newton's law.
Why does distance have such a big effect?
Gravity follows an inverse-square law: the force is proportional to 1/r². Doubling the distance reduces the force to one quarter, and tripling it reduces the force to one ninth.
Is gravitational force always attractive?
Yes. Unlike electric charges, mass produces only attractive gravitational force — there is no known repulsive gravity between ordinary masses.