🚀 Astronomical Unit Converter

Convert between AU, kilometers, meters, miles, light-years, and parsecs

🌟 IAU Standard Precision: This converter uses the exact International Astronomical Union (IAU) definition: 1 AU = 149,597,870,700 meters. Perfect for astronomy students, space enthusiasts, and scientific calculations.

Quick Reference Guide

What is an Astronomical Unit (AU)?

An astronomical unit is the average distance between Earth and the Sun. Since 2012, the IAU defines 1 AU as exactly 149,597,870,700 meters (about 150 million kilometers or 93 million miles). It's the standard unit for measuring distances within our Solar System.

Common Conversions

Why Use Different Units?

Astronomical Units (AU): Perfect for Solar System distances. Earth is 1 AU from the Sun, Mars is 1.52 AU, Jupiter is 5.2 AU.

Light-years: Used for stellar and galactic distances. Proxima Centauri (nearest star) is 4.24 light-years away.

Parsecs: Standard in professional astronomy research. One parsec equals about 3.26 light-years.

Kilometers/Miles: Useful for spacecraft trajectories and public communication.

How to Use This Converter

  1. Enter the distance value you want to convert
  2. Select the unit you're converting from
  3. Click "Convert Distance" to see results in all supported units
  4. Results update instantly showing equivalent values
💡 Pro Tip: The converter works in both directions! You can convert from any unit to any other unit. Try converting 1 AU to see its equivalent in all other astronomical distance units.

Practical Examples

Example 1: Earth to Sun Distance

Input: 1 AU
Result: 149,597,870.7 km or 92,955,807 miles
Context: This is the baseline for all Solar System measurements.

Example 2: Mars Orbit

Input: 1.52 AU (average distance)
Result: 227,388,683 km
Context: Mars orbits about 50% farther from the Sun than Earth.

Example 3: Proxima Centauri (Nearest Star)

Input: 4.24 light-years
Result: ≈ 268,000 AU or 40 trillion km
Context: Shows the vast difference between planetary and stellar scales.

Example 4: Jupiter's Distance

Input: 5.2 AU
Result: 778 million km
Context: Jupiter is about 5 times farther from the Sun than Earth.