Stellar Parallax Calculator
Enter a star's parallax angle in arcseconds to instantly calculate its distance in parsecs and light-years using d = 1/p.
Parallax Input
arcsec
Quick examples
Distance Results
Enter a parallax angle and click Calculate.
Parallax (arcsec)
Distance in Parsecs
Distance in Light-Years
Distance in Astronomical Units
Formula: d (pc) = 1 / p (arcsec)
· 1 pc = 3.26156 ly = 206,265 AU
Results copied!
Summary
Enter a star's parallax angle in arcseconds to instantly calculate its distance in parsecs and light-years using d = 1/p.
How it works
- Enter the parallax angle in arcseconds. For most stars this is a very small number (e.g., Proxima Centauri = 0.7687″).
- The calculator applies d (pc) = 1 / p, where p is in arcseconds.
- Distance in light-years is found by multiplying parsecs by 3.26156.
- Distance in astronomical units is parsecs × 206,265.
- Results update instantly as you type, with uncertainty propagation if you enter a ±error.
Use cases
- Convert Hipparcos or Gaia catalog parallax values to distances for a star.
- Solve introductory astronomy homework involving the parsec definition.
- Cross-check published distances against measured parallax angles.
- Explore how distance uncertainty scales with parallax measurement error.
- Build intuition for how far away stars at different parallaxes actually are.
- Quickly compare distances for a list of nearby stars.
Frequently Asked Questions
Last updated: 2026-07-22 ·
Reviewed by Nham Vu