Relativity Calculators
Last updated: October 2026
Gravitational Time Dilation Calculator
Calculates how gravity slows time near massive objects using Einstein's general relativity.
Relativistic Energy Calculator
Calculate the total relativistic energy E = γmc² and kinetic energy (γ − 1)mc² of a particle from its rest mass and speed, in joules, MeV or GeV.
Relativistic Doppler Shift Calculator
Computes the observed frequency of light or radio waves when the source and observer move relative to each other at relativistic speeds.
Mass-Energy Equivalence Calculator
Converts mass directly into its equivalent energy using Einstein's E = mc².
Lorentz Factor Calculator
Compute the Lorentz factor γ = 1/√(1 − (v/c)²), the central quantity of special relativity that scales time dilation, length contraction, relativistic mass, momentum, and energy.
Time Dilation Calculator
Compute the time experienced by a stationary observer for a moving clock that ticks through a given proper time, using special relativity.
Cosmological Redshift Calculator
Compute the cosmological redshift (z), recession velocity, or distance of a galaxy from its observed vs.
Lorentz Transformation Calculator
Transforms the spacetime coordinates (x, t) of an event from one inertial reference frame to another moving at relativistic velocity.
Schwarzschild Radius Calculator
Computes the Schwarzschild radius — the critical size at which any mass becomes a black hole.