Calculate time dilation and trip duration for relativistic space travel.
Flight Parameters
Must be less than 100%. Light speed c ≈ 300,000 km/s.
Journey Statistics
Enter distance and speed
About this calculator
Quick Reference
Speed of Light (c)299,792,458 m/s
Proxima Centauri4.24 ly away
Galactic Center~26,000 ly away
Andromeda Galaxy2.5 million ly away
Overview
Experience the effects of Special Relativity! As you travel closer to the speed of light, time slows down for you relative to a stationary observer on Earth. This calculator helps you plan your interstellar trips.
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Pro Tips
The 'Lorentz Factor' indicates how much time is dilated. A factor of 10 means 10 years on Earth pass for every 1 year on the ship.
Speeds are input as a percentage of 'c' (the speed of light).
Notice how time dilation becomes extreme as you approach 99.9% of light speed.
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Fun Facts
"If you could travel at 99.999% the speed of light to the Andromeda Galaxy (2.5 million light years away), the trip would only take about 11 years for you!"
"GPS satellites must account for time dilation; otherwise, your navigation would drift by kilometers every day."
"The 'Twin Paradox' is a famous thought experiment where a space-travelling twin returns younger than their earthbound sibling."
