Parsec to Light-Year Converter

About this calculator

A parsec (parallax-second) is the distance at which one astronomical unit — the Earth-Sun distance — subtends an angle of exactly one arcsecond, defined geometrically rather than by light travel time. It works out to about 3.2616 light-years, 206,265 astronomical units, or 3.0857×10¹³ kilometers, and it's the unit astronomers get directly from parallax measurements rather than deriving.

This converter takes a distance in parsecs and returns the equivalent in light-years, astronomical units, and kilometers using the exact IAU-defined constants, so you don't have to remember the conversion factors or risk rounding errors. Astronomy students, amateur stargazers, and science writers use it to translate catalog distances — which are usually given in parsecs or kiloparsecs from parallax or standard-candle measurements — into the light-year figures that are more intuitive for a general audience.