Time dilation
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Formula
t′ = t / √(1 − v²/c²)
Worked example
Given: Proper time = 1 yr; Speed = 0.9 c
Result: Observer time = 2.29 yr; Lorentz factor γ = 2.29
How it is calculated
1. Enter the values you know. 2. The calculator converts them to base units and applies the formula. 3. The result is shown in the unit you choose.
Frequently asked questions
How do I calculate it?
Formula: t′ = t / √(1 − v²/c²). Given: Proper time = 1 yr; Speed = 0.9 c. Result: Observer time = 2.29 yr; Lorentz factor γ = 2.29.
Is the calculator free and private?
Yes. It is free, needs no sign-up and runs in your browser — the numbers you type stay on your device.