How many light-years are in a parsec?

One parsec equals about 3.26156 light-years. It is defined as 648000/π astronomical units, the distance at which one AU subtends one arcsecond.

Why do astronomers use parsecs?

The parsec comes directly from parallax measurement — a star at one parsec shows a parallax angle of one arcsecond — so it is natural for cataloguing stellar distances.

How do I convert light-years back to parsecs?

Divide the number of light-years by 3.26156. For example, 10 light-years ÷ 3.26156 ≈ 3.066 parsecs. The tool does this automatically when you type in the light-years field.

How far is a parsec in kilometres?

One parsec is about 3.0857 × 10¹³ km, or roughly 30.857 trillion kilometres — about 206,265 astronomical units.

How far is the nearest star in parsecs?

Proxima Centauri is about 1.30 parsecs away, which is roughly 4.24 light-years. That single light-year gap shows how close the two units are in size.

What is a kiloparsec or megaparsec?

A kiloparsec (kpc) is 1,000 parsecs and a megaparsec (Mpc) is 1,000,000 parsecs. Kiloparsecs measure galactic scales and megaparsecs measure distances between galaxies.

Is anything sent to a server?

No. The conversion runs entirely in your browser, with no network requests.

Parsecs to Light-Years Converter

Parsecs to light-years

A parsec is the distance at which one astronomical unit subtends an angle of one arcsecond — mathematically 648000/π AU. That equals about 3.26156 light-years, or roughly 30.857 trillion kilometres. Both units measure the vast distances between stars, so converting between them is a routine step in astronomy and astrophysics.

How it works

The converter uses the exact constant 1 parsec = 3.26156377716743 light-years and works in both directions:

light-years = parsecs × 3.26156
parsecs     = light-years ÷ 3.26156

Type a value in either field and the other updates instantly. Results are formatted with more decimals for small numbers and scientific notation for very large or very small values.

Example

Convert 1.3 parsecs (about the distance to Proxima Centauri):

1.3 × 3.26156 ≈ 4.240 light-years

And the reverse, 10 light-years:

10 ÷ 3.26156 ≈ 3.066 parsecs

Parsecs	Light-years
1	3.26156
1.3	4.240
10	32.6156
1000	3261.56

The conversion runs entirely in your browser — nothing is uploaded.