Interstellar Travel Time Calculator
Estimate interstellar travel time to a distant star, including relativistic time dilation experienced by the traveler.
What this calculator estimates
This tool estimates how long an interstellar journey would take, both as measured by observers on Earth and as experienced by travelers aboard a spacecraft moving at relativistic speed, accounting for time dilation.
The formula
Earth-frame travel time is tearth = d / (βc), where d is distance in light-years and β is speed as a fraction of light speed. Due to time dilation, the traveler experiences less elapsed time: ttraveler = tearth / γ, where γ = 1/√(1 − β²) is the Lorentz factor. At higher fractions of light speed, the traveler’s experienced time becomes much shorter than the time that passes on Earth.
This calculator is for general educational and conceptual exploration, not a mission-design tool.