# Time Dilation Calculator

Enter the total time interval and the velocity of the observer to calculate the relative time seen by that observer. This time dilation calculator can also be considered a relative time calculator.

## Time Dilation Formula

The following equation can be used to calculate the relative time seen by an observer traveling at fast speeds.

RT = t * √(1 – v²/c²)

• Where RT is the relative time (seconds)
• t is the actually time (seconds)
• v is the velocity of the observer
• c is the speed of light. (299792458 m/s)

As with most things involving relativity, the speed of light is present in this equation. For any time to be noticeably different the observer must be traveling at extremely fast speeds. If you play around with the values in the calculator you can see this effect.

Digging a little deeper into this formula, you may notice that this takes a square root of a value. What if this value is less than 0 or negative? Well, it cant be. That’s because the denominator for the equation is the speed of light, and nothing can travel faster than the speed of light. As the observer velocity approaches the speed of light, the relative time will approach 0.