Parallax distance calculator
Enter the star's annual parallax, as listed in catalogues such as Gaia, to get its distance from Earth.
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How to use it
- Enter parallax and angle unit.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
d (pc) = 1 ÷ p (arcseconds). 1 parsec = 648000 ÷ π au exactly, about 3.26156 light years.
Example
Inputs: Parallax = 768.0665, Angle unit = Milliarcseconds (mas). Result: Distance in parsecs: 1.30197 pc; In light years: 4.24646 ly; In astronomical units: 268,551 au.
Limits and caveats
- Very small parallaxes carry a large relative error, so distances to far stars are approximate.
- Catalogue corrections such as the Gaia zero-point offset are not applied.
Questions about this tool
What is a parsec?
The distance at which the radius of Earth's orbit spans one arcsecond, about 3.26 light years.
How far is the nearest star after the Sun?
Proxima Centauri, with a parallax of about 768 mas, lies about 4.25 light years away.
Why does parallax shrink for farther stars?
The angle is inversely proportional to distance, so farther stars shift less over the year.