Astronomical Unit Converter Formula

Understand the math behind the astronomical unit converter. Each variable explained with a worked example.

Use the Astronomical Unit Converter

Formulas Used

Kilometres

km = au * 149597870.7

Miles

miles = au * 92955807.3

Light-Minutes

light_minutes = au * 8.3167

Variables

VariableDescriptionDefault
auDistance(AU)1

How It Works

The Astronomical Unit

1 AU = 149 597 870.7 km (exact, IAU 2012)

Light takes about 8.317 minutes to travel 1 AU. The AU is the fundamental baseline for solar system distances.

Worked Example

Jupiter orbits at about 5.2 AU.

au = 5.2
  1. 01km = 5.2 × 149 597 870.7 ≈ 778 million km
  2. 02Light-minutes = 5.2 × 8.317 = 43.2
  3. 03Light takes about 43 minutes to reach Jupiter from the Sun.

Ready to run the numbers?

Open Astronomical Unit Converter