Calculate relativistic time dilation between a moving frame and a stationary observer.
A moving clock runs slow relative to a stationary observer by exactly the Lorentz factor. At 0.8c the factor is 1.667, so one year aboard corresponds to twenty months outside. Time dilation is measured routinely in particle lifetimes and must be corrected for in satellite navigation, where it is a real engineering constraint.
Time Dilation
Δt = γ Δτ, with γ = 1 ÷ √(1 − v²/c²)
Δt = γ Δτ, with γ = 1 ÷ √(1 − v²/c²) A moving clock runs slow relative to a stationary observer by exactly the Lorentz factor. At 0.8c the factor is 1.667, so one year aboard corresponds to twenty months outside.
Time dilation is measured routinely in particle lifetimes and must be corrected for in satellite navigation, where it is a real engineering constraint.
This calculator takes 2 inputs: Speed as a fraction of light speed, Time measured in the moving frame. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.