Gravitational Force Calculator

Use F = Gm₁m₂/r² with adjustable mass and separation units.

Mass 1

Mass 2

Center-to-center distance

—force N

—force kN

—force lbf

—G used

—Newtonian point-mass model: F = Gm₁m₂/r².

These are idealized classical-physics calculations. Real systems can differ because of air resistance, friction, deformation, measurement uncertainty, non-constant forces, or other effects not included in the selected model.

Physics model preflight

Check the governing model before trusting the number

Newtonian point/spherical-mass gravity

F = Gm₁m₂/r²

Reading the current native inputs…

Masses are non-negative and center-to-center separation must be positive. This is an idealized educational model: unit consistency and valid inputs do not guarantee that omitted effects are negligible in a real system.

State the model before trusting the number

Classical formulas are only as good as their assumptions and units. Air resistance, damping, deformation, non-constant forces and measurement uncertainty are not silently invented when the selected model does not include them.

Governing physics model

F = Gm₁m₂/r² — Newtonian point/spherical-mass gravity.

How to verify the result

Doubling either mass should double force; doubling separation should reduce force to one quarter.

Domain and assumption boundary

Masses are non-negative and center-to-center separation must be positive. The calculator does not silently add drag, damping, deformation, varying fields, relativistic effects, measurement uncertainty, or geometry that the selected model does not contain.