ConverterHub

Parsec to Light-Year Converter

Enter a distance in parsecs to convert to light-years and astronomical units.

Result

4.24 ly
268,144 AU

How it is calculated

The conversion is a fixed multiplication: light-years = parsecs × 3.2615637772 and AU = parsecs × 206264.806. The input is a distance in parsecs (pc), the light-year result is rounded to two decimals, and the astronomical-unit result is rounded to a whole number and shown with thousands separators. The input must be zero or greater, since a distance cannot be negative; a negative value returns no result. Zero returns 0.00 ly. Because of the rounding, very small distances lose detail: 0.001 pc shows as 0.00 ly although it is still 206 AU, so for distances well below one parsec read the AU line. The tool converts one way only, from parsecs to light-years.

Worked example

Convert a distance of 1.3 parsecs. Light-years: 1.3 × 3.2615637772 = 4.2400, which the tool shows as 4.24 ly. In astronomical units: 1.3 × 206264.806 = 268,144.2, shown as 268,144 AU. So 1.3 pc is a little over four light-years, or roughly 268 thousand times the Earth-Sun distance.

Try this example →

Common mistakes

  • Typing a distance in light-years into the parsec field. The result is then 3.26 times too large; to go from light-years to parsecs you divide by 3.2616, which this tool does not do.
  • Using kiloparsecs or megaparsecs without scaling. Galactic distances are often given in kpc: 8 kpc must be entered as 8000, which the tool converts to 26,092.51 ly.
  • Reading 0.00 ly for a small distance as zero. The light-year line has only two decimals, so check the AU line instead (0.001 pc is 206 AU).
  • Confusing the parsec with a unit of time. It is a distance, about 3.26 light-years, and the light-year is a distance too, not a duration.
  • Entering a negative number to represent direction. Only values of zero or more are accepted.

About this calculator

A parsec (short for "parallax of one arcsecond") is the distance at which a star would show a parallax shift of exactly one arcsecond as Earth orbits the Sun — it's the unit astronomers derive directly from parallax measurements. A light-year, by contrast, is simply the distance light travels in one Julian year.

This converter applies 1 pc = 3.2616 light-years ≈ 206,265 astronomical units, letting you move between the professional astronomy unit (parsecs) and the more intuitive public-facing one (light-years). Astronomy students, educators and stargazers use it to translate catalog distances — often published in parsecs — into figures that are easier to visualize.

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