Convert length and distance units — meters, feet, inches, kilometers, miles, light years and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 ly | 0.000306578 pc | |
| 0.01 ly | 0.00306578 pc | |
| 0.1 ly | 0.0306578 pc | |
| 1 ly | 0.306578 pc | |
| 5 ly | 1.53289 pc | |
| 10 ly | 3.06578 pc | |
| 50 ly | 15.3289 pc | |
| 100 ly | 30.6578 pc | |
| 1000 ly | 306.578 pc |
Multiply the number of Light Years by 0.306578 to get Parsecs. Formula: pc = ly × 0.306578. Example: 10 ly × 0.306578 = 3.06578 pc. To reverse, divide Parsecs by 0.306578 to get Light Years.
| Light Year (ly) | Parsec (pc) |
|---|---|
| 0.001 ly | 0.000306578 pc |
| 0.01 ly | 0.00306578 pc |
| 0.1 ly | 0.0306578 pc |
| 0.5 ly | 0.153289 pc |
| 1 ly | 0.306578 pc |
| 2 ly | 0.613156 pc |
| 5 ly | 1.53289 pc |
| 10 ly | 3.06578 pc |
| 20 ly | 6.13156 pc |
| 50 ly | 15.3289 pc |
| 100 ly | 30.6578 pc |
| 250 ly | 76.6445 pc |
| 500 ly | 153.289 pc |
| 1000 ly | 306.578 pc |
| 10000 ly | 3065.78 pc |
To convert Light Year to Parsec, multiply by 0.306578. Example: 10 ly = 3.06578 pc
To convert Parsec back to Light Year, divide by 0.306578 (multiply by 3.26181). Use the swap button above.
Start with 100 Light Years = 30.6578 pc as your reference point. Scale up or down from there.
1 ly = 0.3066 parsecs (1 pc = 3.26 ly). This is the most important conversion in observational astronomy — professional papers use parsecs while public communication uses light-years. Every astronomer converts between them routinely.
Stellar catalogues (Hipparcos, Gaia) express distances in parsecs. Science communicators and educators convert to light-years for public reporting — Proxima Centauri at 1.295 pc = 4.24 ly is the most cited example.
Galaxy clusters are described in megaparsecs (Virgo Cluster: ~16 Mpc = 52 million ly) in technical papers. Science journalists convert megaparsecs to million-light-years for accessible reporting to general audiences.
Galaxy redshift surveys (SDSS, DESI) report distances in megaparsecs. Educators and outreach professionals convert to light-years to make survey scales tangible: "SDSS mapped galaxies out to 5 billion light-years (1.5 Gpc)."
Exoplanet catalogues report host star distances in parsecs. Popular exoplanet databases like NASA Exoplanet Archive convert to light-years for public-facing descriptions — requiring systematic ly-to-parsec conversion.
The easiest way to define a parsec for astronomy students is through the light-year: "1 parsec = 3.26 light-years." This conversion is the entry point to understanding why astronomers prefer parsecs over the more familiar light-year.
The Light Year is a unit of Length measurement (symbol: ly). 1 ly = 0.306578 pc. Used in scientific and practical Length measurement applications.
The Parsec is a unit of Length measurement (symbol: pc). It is part of an internationally recognised measurement system used alongside the Light Year.
The light-year first appeared in a German publication in 1851 written by Otto Ule as a way to make stellar distances comprehensible to general audiences — it was not coined by professional astronomers. It equals the distance light travels in one Julian year: exactly 9,460,730,472,580.8 kilometres. Professional astronomers often prefer parsecs (which relate directly to parallax measurements), but the light-year became the public's unit of choice for cosmic distance because it connects the familiar concept of speed with cosmic scale. One light-year equals about 63,241 astronomical units.
The parsec was introduced in 1913 by British astronomer Herbert Hall Turner. It equals the distance at which 1 astronomical unit subtends 1 arcsecond — approximately 3.086×10¹³ kilometres or 3.26 light-years. The name blends 'parallax' and 'arcsecond'. Professional astronomers strongly prefer parsecs because parallax directly yields distance in parsecs without intermediate calculation.
Common use: Light Year to Parsec conversion is needed when working with international standards, scientific publications, or reference materials that use different unit systems for Length measurement.