Time Dilation Calculator

About this calculator

This calculator applies special relativity's time dilation formula, Δt' = γ·Δt, where γ is the Lorentz factor 1/√(1−v²/c²). As an object's speed v approaches the speed of light c, γ grows without bound, meaning a clock moving relative to a stationary observer ticks slower from that observer's point of view — a real, measured effect, not an illusion of perspective.

Particle physicists use this to explain why fast-moving muons created in the upper atmosphere survive long enough to reach the ground despite their short rest-frame lifetime, and satellite engineers must correct GPS clocks for exactly this effect (combined with gravitational time dilation) to keep positioning accurate to within meters. Physics students working through the twin paradox, astrophysics enthusiasts, and engineers dealing with high-precision timing systems all use this calculator to see how dramatically time stretches as speed approaches light speed.