Convert kilometers to astronomical units
1 km = 0.00000000668458712227 au — exactly. Both units are defined against the SI, so this factor is a fraction, not an approximation.
6.68458712227e-9au
As a fraction: 10/1495978707
1 km = 0.00000000668458712227 au
How to convert kilometers to astronomical units
Multiply the number of kilometers by 0.00000000668458712227 to get astronomical units.
Astronomical unit: Fixed at exactly 149 597 870 700 m by the IAU in 2012.
Kilometer to Astronomical unit conversion table
| Kilometers (km) | Astronomical units (au) |
|---|---|
| 1 km | 6.6845871e-9 |
| 2 km | 1.3369174e-8 |
| 3 km | 2.0053761e-8 |
| 5 km | 3.3422936e-8 |
| 10 km | 6.6845871e-8 |
| 20 km | 0.000 000 133 691 74 |
| 25 km | 0.000 000 167 114 68 |
| 50 km | 0.000 000 334 229 36 |
| 100 km | 0.000 000 668 458 71 |
| 250 km | 0.000 001 671 146 8 |
| 500 km | 0.000 003 342 293 6 |
| 1000 km | 0.000 006 684 587 1 |
Astronomical unit to Kilometer conversion table
| Astronomical units (au) | Kilometers (km) |
|---|---|
| 1 au | 149 597 870 |
| 2 au | 299 195 740 |
| 3 au | 448 793 610 |
| 5 au | 747 989 350 |
| 10 au | 1 495 978 700 |
| 20 au | 2 991 957 400 |
| 25 au | 3 739 946 800 |
| 50 au | 7 479 893 500 |
| 100 au | 14 959 787 000 |
| 250 au | 37 399 468 000 |
| 500 au | 74 798 935 000 |
| 1000 au | 149 597 870 000 |
Frequently asked
How many astronomical units are in a kilometer?
One kilometer equals 6.684587122e-9 astronomical units (km → au). That figure is exact, not rounded.
How do you convert kilometers to astronomical units?
Multiply the number of kilometers by 0.00000000668458712227 to get astronomical units.
What is 1 au in kilometers?
One astronomical unit is 149597870.7 kilometers.
What is 10 km in au?
10 km = 6.6845871e-8 au.
What exactly is a astronomical unit?
Fixed at exactly 149 597 870 700 m by the IAU in 2012.