Time Dilation Calculator
⚛ Modern physics. Use the Time dilation formula to find time seen by an observer, proper time t₀ (on the clock), speed: pick the value you want, type the others, and the answer updates as you go.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Time seen by an observer | s |
| Proper time t₀ (on the clock) | s |
| Speed | m/s |
Worked example
Find the time seen by an observer when Proper time t₀ (on the clock) = 1 s, Speed = 2.596 × 10⁸ m/s.
Using t = t0/(√(1 - v²/c²)): Time seen by an observer = 1.9994 s.
Frequently asked questions
What is the formula for Time dilation?
t = t0/(√(1 - v²/c²)).
What do the letters stand for, and what units are used?
Time seen by an observer in s, Proper time t₀ (on the clock) in s, Speed in m/s.
How do you calculate time seen by an observer?
Put the values into t = t0/(√(1 - v²/c²)). For example, with Proper time t₀ (on the clock) = 1 s, Speed = 2.596 × 10⁸ m/s, time seen by an observer = 1.9994 s.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (time seen by an observer, proper time t₀ (on the clock), speed) and fill in the others: it rearranges the formula for you.
