Light-Year to Kilometres Converter Formula

Understand the math behind the light-year to kilometres converter. Each variable explained with a worked example.

Use the Light-Year to Kilometres Converter

Formulas Used

Kilometres

km = light_years * 9460730472580.8

Astronomical Units

au = light_years * 63241.077

Parsecs

parsec = light_years / 3.26156

Variables

VariableDescriptionDefault
light_yearsDistance(ly)1

How It Works

Light-Year Conversion

A light-year is the distance light travels in one Julian year (365.25 days).

1 ly = 9 460 730 472 580.8 km

From: c × t = 299 792.458 km/s × 31 557 600 s

Worked Example

Proxima Centauri is about 4.246 ly away.

light_years = 4.246
  1. 01km = 4.246 × 9 460 730 472 580.8
  2. 02≈ 4.017 × 10¹³ km
  3. 03AU = 4.246 × 63241 ≈ 268 521 AU
  4. 04pc = 4.246 / 3.2616 ≈ 1.302 pc

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