Time Dilation Calculator Formula

Understand the math behind the time dilation calculator. Each variable explained with a worked example.

Formulas Used

Dilated Time (observer)

dilated_time = proper_time / sqrt(1 - pow(velocity_fraction, 2))

Lorentz Factor (gamma)

lorentz_factor = 1 / sqrt(1 - pow(velocity_fraction, 2))

Variables

VariableDescriptionDefault
proper_timeProper Time (moving frame)(s)1
velocity_fractionVelocity (fraction of c)0.9

How It Works

Time Dilation

Special relativity predicts that time passes more slowly for objects in relative motion.

Formula

t = t_0 / sqrt(1 - v²/c²) = gamma * t_0

where t_0 is the proper time (measured in the moving frame) and gamma = 1/sqrt(1 - v²/c²) is the Lorentz factor.

Worked Example

1 second of proper time at 90% the speed of light.

proper_time = 1velocity_fraction = 0.9
  1. 01gamma = 1 / sqrt(1 - 0.9²)
  2. 02gamma = 1 / sqrt(1 - 0.81)
  3. 03gamma = 1 / sqrt(0.19)
  4. 04gamma = 1 / 0.4359 = 2.294
  5. 05t = 1 * 2.294 = 2.294 s (observed from outside)

Ready to run the numbers?

Open Time Dilation Calculator