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Distance In Light Years Calculator

Work out distance in light years instantly with clear inputs, formula shown and shareable results.

About Distance In Light Years Calculator

A light year is the distance light covers in a Julian year, 9.4607e15 m. Proxima Centauri at 4.24 light years is 1.30 parsecs, 268,000 astronomical units or 4.01e13 km. Because the astronomical unit is Earth's orbital radius, it is the natural unit inside a solar system and hopelessly small between stars.

Formulas

Light year

1 ly = 9.4607304725808e15 m

Parsec

1 pc = 3.0857e16 m = 3.2616 ly

Worked example

With the default values below, Distance In Light Years Calculator returns Distance In Light Years of 4.2400. Change any input above and every figure here is recalculated in your browser.

Inputs used

Distanceminimum 0
4.24
Unit of that figureone of Light years, Parsecs, Astronomical units, Kilometres
Light years

Results

Distance In Light Years
4.2400
Distance In Parsecs
1.3000
Distance In Astronomical Units
2.68142 × 10⁵
Distance In Kilometres
4.01135 × 10¹³

Step by step

  1. 1Values used
  2. 2Light year
  3. 3Parsec
  4. 4Distance In Light Years= 4.2400
  5. 5Distance In Parsecs= 1.3000
  6. 6Distance In Astronomical Units= 268,142.00000
  7. 7Distance In Kilometres= 40,113,500,000,000.00000

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Is a light year a time or a distance?

A distance - how far light travels in a year. The confusion is common enough that it appears in film dialogue regularly.

Why do astronomers prefer parsecs?

Because parallax measurement gives distance in parsecs directly: one parsec is the distance at which Earth's orbit subtends one arcsecond.

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