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
| Variable | Description | Default |
|---|---|---|
proper_time | Proper Time (moving frame)(s) | 1 |
velocity_fraction | Velocity (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.
- 01gamma = 1 / sqrt(1 - 0.9²)
- 02gamma = 1 / sqrt(1 - 0.81)
- 03gamma = 1 / sqrt(0.19)
- 04gamma = 1 / 0.4359 = 2.294
- 05t = 1 * 2.294 = 2.294 s (observed from outside)
Frequently Asked Questions
Is time dilation real?
Absolutely. It has been confirmed by comparing atomic clocks on jets to ground clocks, by muon lifetime measurements, and by GPS satellite corrections.
What is the twin paradox?
If one twin travels at high speed and returns, they will have aged less than the stay-at-home twin. This is not a paradox but a real prediction confirmed by experiment.
Why does GPS need relativity corrections?
GPS satellites move fast (time dilation) and are in weaker gravity (gravitational time dilation). Without corrections, GPS would drift by about 10 km per day.
Ready to run the numbers?
Open Time Dilation Calculator