Reduced Mass Calculator

About this calculator

This calculator computes reduced mass, μ = m₁·m₂/(m₁+m₂), the effective single mass that lets a two-body problem — like two masses orbiting their common center of gravity, or two atoms vibrating in a diatomic molecule — be treated mathematically as a one-body problem orbiting or oscillating around a fixed point. When one mass is much larger than the other, μ approaches the smaller mass, which is why Earth's orbital mechanics can often ignore the Sun's slight wobble.

Physics and chemistry students working through classical mechanics or quantum mechanics problem sets, and researchers modeling binary star systems, molecular vibration spectra, or particle collisions use this. Enter the two masses to get the reduced mass.