Instant · Precise · Universal
32 units available
6 categories total
To convert AU to km: multiply by 149,597,870.7. To convert AU to light-years: divide by 63,241.
1 AU = 149,597,870,700 m ≈ 149.598 Gm ≈ 499 light-seconds ≈ 8.317 light-minutes.
For example, 1 Astronomical Unit (AU) = 23454.79106 Earth's Equatorial Radius (R⊕ (eq)).
| Astronomical Unit (AU) | Earth's Equatorial Radius (R⊕ (eq)) |
|---|---|
| 0.1 | 2345.479106 |
| 0.5 | 11727.39553 |
| 1 | 23454.79106 |
| 2 | 46909.58212 |
| 5 | 117273.9553 |
| 10 | 234547.9106 |
| 25 | 586369.7766 |
| 50 | 1172739.553 |
| 100 | 2345479.106 |
| 500 | 11727395.53 |
| 1000 | 23454791.06 |
The astronomical unit is a unit of length approximating the mean Earth-Sun distance, defined as exactly 149,597,870,700 meters.
1 AU = 149,597,870,700 m ≈ 149.598 Gm ≈ 499 light-seconds ≈ 8.317 light-minutes.
To convert AU to km: multiply by 149,597,870.7. To convert AU to light-years: divide by 63,241.
Spacecraft mission planning, expressing planetary orbit sizes, and solar system scale models.
Light takes about 8 minutes and 20 seconds to travel 1 AU. Mars is about 1.52 AU from the Sun, Jupiter about 5.2 AU.
Thinking the AU is the exact Earth-Sun distance — Earth's actual distance varies from ~147 to ~152 Gm over the year due to orbital eccentricity.
AU makes the solar system manageable: Mercury ≈ 0.39 AU, Venus ≈ 0.72, Earth = 1, Mars ≈ 1.52, Jupiter ≈ 5.2, Saturn ≈ 9.5.
The Earth's equatorial radius is the distance from Earth's center to the equator, approximately 6,378.137 km.
R⊕(eq) = 6,378,137 m = 6,378.137 km. Earth's oblateness = (R_eq − R_pol)/R_eq ≈ 1/298.257.
To convert Earth radii to meters: multiply by 6,378,137.
GPS calculations, satellite orbit determination, map projections, and geophysical modeling.
Earth is not a perfect sphere — the equatorial radius is about 21 km (0.3%) larger than the polar radius due to rotational flattening.
Using the equatorial radius as if Earth were a sphere — for precision, you must account for the oblate spheroid shape.
Earth's equatorial radius (6,378 km) vs. polar radius (6,357 km) shows the planet bulges at the equator due to spinning.



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