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.
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Show this value in all 50 length units
- Gigameters Gm 0.000 001
- Megameters Mm 0.001
- Kilometers km 1
- Hectometers hm 10
- Decameters dam 100
- Meters m 1000
- Decimeters dm 10 000
- Centimeters cm 100 000
- Millimeters mm 1 000 000
- Micrometers µm 1 000 000 000
- Nanometers nm 1 000 000 000 000
- Picometers pm 1 000 000 000 000 000
- Femtometers fm 1e+18
- Inches in 39 370.078 740 2
- Feet ft 3280.839 895 01
- Yards yd 1093.613 298 34
- Miles mi 0.621 371 192 237
- Nautical miles nmi 0.539 956 803 456
- Thous thou 39 370 078.7402
- Hands hh 9842.519 685 04
- Links li 4970.969 537 9
- Spans span 4374.453 193 35
- Cubits cubit 2187.226 596 68
- Ells ell 874.890 638 67
- Fathoms ftm 546.806 649 169
- Rods rd 198.838 781 516
- Chains ch 49.709 695 379
- Furlongs fur 4.970 969 537 9
- Leagues lea 0.207 123 730 746
- Barleycorns barleycorn 118 110.236 22
- US survey feet ft (US) 3280.833 333 33
- US survey miles mi (US) 0.621 369 949 495
- Ångströms Å 10 000 000 000 000
- Microns µ 1 000 000 000
- Bohr radiuss a₀ 18 897 261 259 100
- Planck lengths ℓₚ 6.18714249917e+37
- Astronomical units au 6.68458712227e-9
- Light-years ly 1.05700083402e-13
- Light-seconds ls 0.000 003 335 640 951 98
- Light-minutes lmin 5.55940158664e-8
- Parsecs pc 3.24077928944e-14
- Kiloparsecs kpc 3.24077928944e-17
- Megaparsecs Mpc 3.24077928944e-20
- Solar radiuss R☉ 0.000 001 437 401 178 67
- Earth radiuss R🜨 0.000 156 961 230 576
- Point (DTP)s pt 2 834 645.669 29
- Picas pc 236 220.472 441
- Scandinavian miles mil 0.1
- Versts вер 0.937 382 827 147
- Lis 里 2
Every row is Kilometer (km) converted through the meter, in exact rational arithmetic.
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.