Physics

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Time Dilation Calculator.

Calculate special-relativistic elapsed time at a given speed.

On-device calculationNo signup
01

Set your values

Results update as you type.

Dilated time: 10.60752 s

Dilated time

0.000000s
Lorentz factor: 1.060752 ×

Lorentz factor

0.000000×

Results update automatically as you type.

Use Cases

Physics homework and study

Students can verify time dilation calculations for special relativity problems, understanding how speed affects elapsed time.

Example: Calculate the dilated time for a proper time of 10 s at 0.5c (1.5e8 m/s).

Science communication and curiosity

Enthusiasts can explore the effects of relativistic speeds on time, making abstract concepts tangible.

Example: See how much time passes for a traveler moving at 99% of light speed for 1 year.

Frequently Asked Questions

What does the Time Dilation Calculator do?
It calculates the dilated time (elapsed time for a stationary observer) based on the proper time (time measured by the moving object) and the speed of the object, using the time dilation formula from special relativity.
What units are used for proper time and speed?
Proper time is entered in seconds (s), and speed is entered in meters per second (m/s). The calculator uses these inputs to compute the dilated time in seconds.
Can I use this calculator for speeds close to the speed of light?
Yes, the calculator is designed for any speed, including those near the speed of light. As speed approaches the speed of light, the dilated time becomes significantly larger than the proper time.

Tips & Common Mistakes

Tips

  • Ensure speed is entered in meters per second (m/s) for accurate results.
  • Remember that proper time is the time measured by the moving object itself.
  • For speeds much less than the speed of light, the dilated time is nearly equal to proper time.
  • Use scientific notation for very large or small numbers to avoid errors.

Common Mistakes to Avoid

  • Entering speed in km/h or miles per hour instead of m/s.
  • Confusing proper time with dilated time; proper time is the input, dilated time is the output.
  • Forgetting that the speed of light is about 3e8 m/s, so speeds should be less than that.

Last updated: August 13, 2026