Astronomical units to orbital speed
Type a value in AU to get it in km/s instantly.
29.78km/s
That's about the same as Earth. A year out there lasts about 1 Earth years.
Convert the other way: km/s to AU
What it means
How long is its year?
Kepler’s law here assumes the Sun’s mass and a circular orbit. Real orbits are ellipses, and the semi-major axis is what goes into the formula.
The math
How to convert AU to km/s
Kepler’s third law: period in years = (distance in AU)^1.5, and back again distance = period^(2/3). Orbital speed falls as 29.78 ÷ √distance km/s.
Example: 1 AU = 29.7847 km/s.
Every unit
Your orbit in every unit
Tables
AU to km/s conversion table
| AU | km/s |
|---|---|
| 0.39 AU | 47.6937 km/s |
| 0.72 AU | 35.1016 km/s |
| 1 AU | 29.7847 km/s |
| 1.52 AU | 24.1586 km/s |
| 2.8 AU | 17.7998 km/s |
| 5.2 AU | 13.0615 km/s |
| 9.5 AU | 9.66343 km/s |
| 19.2 AU | 6.7974 km/s |
| 30.1 AU | 5.42888 km/s |
| 39.5 AU | 4.73909 km/s |
| 100 AU | 2.97847 km/s |
km/s to AU conversion table
| km/s | AU |
|---|---|
| 0.39 km/s | 5,832.53 AU |
| 0.72 km/s | 1,711.28 AU |
| 1 km/s | 887.128 AU |
| 1.52 km/s | 383.972 AU |
| 2.8 km/s | 113.154 AU |
| 5.2 km/s | 32.808 AU |
| 9.5 km/s | 9.82968 AU |
| 19.2 km/s | 2.40649 AU |
| 30.1 km/s | 0.97916 AU |
| 39.5 km/s | 0.568581 AU |
| 100 km/s | 0.0887128 AU |
Quick answers
Quick answers
- How many km/s is 1 AU?
- 1 AU is 29.7847 km/s.
- How many km/s is 10 AU?
- 10 AU is 9.41875 km/s.
The units
About these units
Astronomical units (AU)
The Earth–Sun distance, the natural ruler for the solar system.
Orbital speed (km/s)
How fast it travels. Earth manages 29.8 km/s.
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