Time Dilation Calculator

Calculate how time slows down for objects moving at relativistic speeds

Calculation Mode

Proper Time τ (s) - moving frame

Velocity (m/s)

Time Dilation Results

Proper Time τ (moving)

1.0000 s

1.0000e+0 s

Dilated Time t (stationary)

1.3424 s

1.3424e+0 s

Dilation Factor t/τ

1.342358×

Time Runs Slower By

34.2358%

Velocity (β = v/c)

0.667111408c

Lorentz Factor γ

1.342358

Twin Paradox Example

If a twin travels at this velocity for what they experience as 1 year:

Traveling Twin Ages

1.0000 years

Earth Twin Ages

1.3424 years

Dilation at Various Speeds

Velocity (%c)	Dilation Factor γ
10.0%	1.005038×
50.0%	1.154701×
90.0%	2.294157×
99.0%	7.088812×
99.9%	22.366272×

About Time Dilation

According to special relativity, time passes more slowly for a moving observer: t = γτ where τ is the proper time (measured by the moving clock) and t is the time measured by a stationary observer. This effect has been confirmed by experiments with muons and atomic clocks on aircraft.