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The exact value of 1 au in km is 149,597,870.7 km (or 149,597,870,700 meters exactly). This is the official IAU definition of 1 au in km established in 2012. The exact value of 1 astronomical unit in km and miles: 149,597,870.7 km and 92,955,807 miles. The exact value of 1 au since 2012 is fixed at exactly 149,597,870,700 m by the International Astronomical Union. Use this free au calculator to convert au to km, au to ly, and other units.
Last updated: January 23, 2026
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Astronomical Units
1 au
Light Years
0.00001581 ly
Parsecs
0.00000485 pc
Sun Radii
214.834521 R☉
Meters
149,597,870,700 m
Kilometers
149,597,870.7 km
Miles
92,955,807.27 mi
Key Facts:
Exact conversion
1 au = 149,597,870,700 m
Uses the International Astronomical Union's exact 2012 definition
Astronomical units
AU, Light Years, Parsecs, Sun Radii
Convert between AU, light years, parsecs, Sun radii, and standard units
Use cases
Planet Distances, Orbital Calculations
Ideal for measuring distances between planets and other Solar System objects
Applications
Research, Education, Space Missions
Convert distances for astronomy research, education, and space mission planning
Speed
Instant calculations
See results in all units immediately as you enter or change values
Learning
Understanding Solar System Scale
Helps visualize and understand the vast distances in our Solar System and beyond
For 1 astronomical unit:
Kilometers
149,597,870.7 km
Miles
92,955,807 mi
The exact value of 1 au in km is 149,597,870.7 kilometers (or 149,597,870,700 meters exactly). This is the official IAU definition of 1 au in km (or iau definition of 1 au in km) established in 2012. The exact value of 1 astronomical unit in km and miles (or exact value of 1 astronomical unit in kilometers): 149,597,870.7 km and 92,955,807.273 miles. The exact value of 1 au since 2012 (or 1 au exact value since 2012) is fixed at exactly 149,597,870,700 m by the International Astronomical Union. Also known as exact value of 1 au in km iau definition 2012, exact definition of 1 au in km since 2012, 1 au exact value km iau, 1 au exact value iau, or 1 au exact value iau 2012.
An au calculator (or au calculator) converts between astronomical units and other distance units. To convert au to km (or au to km, 1 au to km, au in km): multiply AU by 149,597,870.7. Example: 9.5 au to km = 9.5 × 149,597,870.7 = 1,421,179,771.65 km. The au to km formula: km = au × 149,597,870.7. Also supports au to ly (astronomical unit to light year), au to kilometers (or au in kilometers), astronomical unit to miles, and km to au conversion. Perfect for calculating 1 au distance in km exact value and other conversions.
The iau 2012 resolution b2 astronomical unit 149597870700 m exact established the exact value. The exact value of 1 au in km iau 2012 (or exact value of 1 au in km iau definition) is exactly 149,597,870,700 meters. Also known as 1 au exact value km, 1 au in km exact, 1 au exact km, 1 au in kilometers exact value, 1 au exact value in km, 1 au in light years exact value, 1 astronomical unit in miles exact, 1 au in million miles, or exact value of 1 au in km nasa. The exact definition of 1 au in km iau provides a precise reference for astronomical calculations. Learn how to calculate au using this definition.
Our astronomical unit calculator uses the International Astronomical Union's (IAU) 2012 definition, which fixed the astronomical unit as exactly 149,597,870,700 meters. When you enter a distance value in any unit, the calculator first converts it to meters, then displays the equivalent in astronomical units and all other supported units.
Astronomical Unit Definition:1 au = 149,597,870,700 m (exactly)AU to Kilometers:km = au × 149,597,870.7AU to Light Years:ly = au × 0.000015813AU to Parsecs:pc = au × 0.000004848All conversions are based on the IAU 2012 standard definition and international astronomical conventions.
An astronomical unit (symbol: au) is a unit of length used primarily in astronomy to measure distances within the Solar System. It was originally defined as the average distance between Earth and the Sun, though the IAU now defines it as exactly 149,597,870,700 meters.
Originally, the astronomical unit was defined as the average distance between Earth and the Sun, approximately 150 million kilometers. This made it convenient for expressing distances within the Solar System.
Average Earth-Sun distance ≈ 1 au
The IAU fixed the astronomical unit as exactly 149,597,870,700 meters in 2012. This provides a precise, unchanging reference for astronomical calculations, independent of Earth's orbital variations.
1 au = 149,597,870,700 m (exact)
The measurement of the astronomical unit has a long and fascinating history:
These three units serve different purposes in astronomy:
Best for Solar System distances. 1 au = 149,597,870,700 m. Light travels this distance in about 8 minutes 20 seconds.
Use: Planet distances, asteroid orbits
Distance light travels in one year. 1 ly ≈ 9.461 × 10¹⁵ m ≈ 63,241 au. Used for interstellar distances.
Use: Star distances, galaxy measurements
Distance at which 1 au subtends 1 arcsecond. 1 pc ≈ 206,264.8 au ≈ 3.26 ly. Used in stellar astronomy.
Use: Stellar distances, parallax measurements
This calculator is essential for various real-world applications:
Convert distances for astronomy research, space mission planning, and understanding planetary orbits. Essential for calculating travel times and orbital mechanics in the Solar System.
Help students understand the scale of the Solar System. Convert between familiar units (km, miles) and astronomical units to visualize planetary distances.
Convert distances for planning space missions, calculating travel times, and understanding the scale of interplanetary distances. Essential for mission design and navigation.
Convert measurements for scientific papers, research calculations, and astronomical data analysis. Ensure accurate conversions using the IAU standard definition.
Need other conversion tools? Check out our length converter and light year conversion.
Get Custom Calculator for Your PlatformResult: 1 au = 149,597,870.7 km = 92,955,807 miles
1 astronomical unit equals approximately 149.6 million kilometers, 93 million miles, or 0.000015813 light years.
Result: 5.2 au = 777,908,927.64 km
Jupiter's average distance from the Sun is 5.2 astronomical units, which equals approximately 778 million kilometers or 484 million miles.
1.5 au ≈
224.4 million km
9.5 au ≈
1.42 billion km
1 ly =
63,241 au
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