Kilometers to Astronomical Units
Snapshot
1 Kilometer equals 6.68e-9 Astronomical Units. Conversion Encyclopedia uses the same fixed conversion basis across the calculator, common values, and reverse page for this page.
- Reference basis: This conversion uses a fixed factor based on canonical reference constants.
- Example: For 2 Kilometers, the result equals 1.34e-8 Astronomical Units.
- Use the reverse page if you need the opposite direction with the same basis.
Use the interactive calculator below for custom values and the common-value table for quick checks.
Converter Calculator
6.68e-9 Astronomical Units (AU)
SwitchExplanation
Formula: Astronomical Units = Kilometers × 6.68e-9. Why: AU, lunar distance, and planetary radius or diameter units are tied to fixed astronomy reference constants, so the route moves through one meter-based normalization path.
Kilometers (km): a metric distance unit often used for planetary, orbital, and near-Earth scale reporting.
Astronomical Units (AU): a standard astronomy distance unit defined exactly as 149,597,870,700 meters, commonly used for Solar System scales.
This route is useful when translating everyday metric or imperial distances into astronomy reference scales, or when expressing astronomy scales in more familiar distance units.
This conversion is purely multiplicative because both units reduce through meters using fixed astronomical or geometric reference constants with no offset.
Common Conversion Values
| Kilometers (km) | Astronomical Units (AU) |
|---|---|
| 1 | 6.68e-9 |
| 2 | 1.34e-8 |
| 5 | 3.34e-8 |
| 10 | 6.68e-8 |
| 100 | 6.68e-7 |
| 1,000 | 0.000006684587 |
Frequently Asked Questions
How is Kilometers to Astronomical Units calculated?
The factor is derived by reducing both units to meters and applying the fixed astronomy reference constants for AU, light-seconds, or lunar-distance scales.
How do I reverse Kilometers to Astronomical Units?
Use the mirror Astronomical Units to Kilometers route; it applies the inverse relationship for the opposite direction with the same assumptions.
Why is 1 kilometer such a small number of astronomical units?
Because 1 astronomical unit is about 149.6 million kilometers, a single kilometer is only a tiny fraction of 1 AU.