Astronomical units to kilometers
Type a value in astronomical units to see it in kilometers straight away, or type in the second box to convert back.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Type the value in the astronomical units box.
- Read the result in kilometers as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
km = au × 149,597,870.7
Multiply the value in astronomical units by 149,597,870.7 to get kilometers.
Example
To convert 25 au to kilometers: 25 × 149,597,870.7 = 3,739,950,000 km.
Conversion table
| Astronomical units (au) | Kilometers (km) |
|---|---|
| 1 | 149,598,000 |
| 2 | 299,196,000 |
| 3 | 448,794,000 |
| 5 | 747,989,000 |
| 10 | 1,495,980,000 |
| 20 | 2,991,960,000 |
| 25 | 3,739,950,000 |
| 50 | 7,479,890,000 |
| 100 | 14,959,800,000 |
| 250 | 37,399,500,000 |
| 500 | 74,798,900,000 |
| 1,000 | 149,598,000,000 |
About the units
- Astronomical unit
- The astronomical unit is exactly 149597870700 meters (IAU 2012), close to the mean Earth to Sun distance.
- Kilometer
- A kilometer is exactly 1000 meters and is the usual unit for road and travel distances.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many kilometers are in one astronomical unit?
1 au = 149,598,000 km exactly.
How do I convert astronomical units to kilometers?
Use km = au × 149,597,870.7. For example, 25 au = 3,739,950,000 km.
How many astronomical units are in one kilometer?
1 km = 6.68459e-9 au.
Are the inch, foot and mile factors exact or rounded?
They are exact by definition. Since the 1959 agreement one inch is exactly 2.54 cm, one foot 0.3048 m and one mile 1609.344 m.
What is the difference between a mile and a nautical mile?
A statute mile is 1609.344 meters and is used on roads. A nautical mile is 1852 meters and is used at sea and in aviation.