An astronomical unit is the mean Earth-Sun distance.
Astronomical units to Angstroms Converter — AU to A
Convert Astronomical unit (AU) to Angstrom (A) using the exact conversion factor (1 astronomical unit = 1.495979e+21 angstrom). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Astronomical units to Angstroms converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
An angstrom is 1e-10 meters.
Result = input x 1.49597871e+11 / 1e-10.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Astronomical units to Angstroms
Astronomical unit and Angstrom both measure length. Astronomical unit is typically associated with used internationally in astronomy for solar-system-scale distances., while Angstrom is typically associated with widely used internationally in chemistry, crystallography, and atomic/molecular physics.
Formula
angstroms = astronomical units × 1.495979e+21
This factor comes from each unit's defined relationship to the category's base unit: 1 astronomical unit equals 149597870700 base units, and 1 angstrom equals 1e-10 base units, so dividing one by the other gives the direct astronomical unit-to-angstrom factor of 1.495979e+21.
Simple example
1 AU × 1.495979e+21 = 1.495979e+21 A
1 astronomical unit = 1.495979e+21 angstroms.
Real-world example
10 AU × 1.495979e+21 = 1.495979e+22 A
10 astronomical units = 1.495979e+22 angstroms.
Conversion table
| Astronomical unit (AU) | Angstrom (A) |
|---|---|
| 1 AU | 1.495979e+21 A |
| 5 AU | 7.479894e+21 A |
| 10 AU | 1.495979e+22 A |
| 21.0975 AU | 3.156141e+22 A |
| 42.195 AU | 6.312282e+22 A |
| 100 AU | 1.495979e+23 A |
Reverse conversion: Angstrom to Astronomical unit
1.495979e+21 A × 6.684587e-22 = 1.000000196 AU
1.495979e+21 angstroms = 1.000000196 astronomical units.
astronomical units = angstroms × 6.684587e-22
For a page dedicated to this direction, see Angstrom to Astronomical unit.
Astronomical unit vs. Angstrom
| Aspect | Astronomical unit | Angstrom |
|---|---|---|
| Family | Non-SI unit accepted for use with SI (astronomical) | non-SI unit, still common in chemistry and crystallography |
| Typical use | Measuring distances within the solar system (planetary orbits) | Atomic and ionic radii in chemistry |
| Where it's used | Used internationally in astronomy for solar-system-scale distances. | Widely used internationally in chemistry, crystallography, and atomic/molecular physics |
Understanding the Astronomical unit
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
Where it's used: Used internationally in astronomy for solar-system-scale distances.
Uses of the Astronomical unit today
- Measuring distances within the solar system (planetary orbits)
- Astronomical calculations and spacecraft navigation
- Popular science communication about the solar system
History of the Astronomical unit
The astronomical unit originated from 17th-19th century attempts to measure the Earth-Sun distance, refined over time using transits of Venus and later radar and spacecraft ranging.
In 2012, the International Astronomical Union fixed the AU at exactly 149,597,870,700 meters, replacing its earlier definition (tied to gravitational calculations) with a simple fixed distance, independent of the slightly-variable actual Earth-Sun distance.
Historical origin. Astronomical unit was not the invention of a single named person; it developed through the process described above.
Understanding the Angstrom
Angstrom (A) measures length. Equal to exactly 10⁻¹⁰ meters (0.1 nanometers) — a scale convenient for describing atomic radii, bond lengths, and crystal structures. It is classified as a non-SI unit, still common in chemistry and crystallography.
Where it's used: Widely used internationally in chemistry, crystallography, and atomic/molecular physics
Uses of the Angstrom today
- Atomic and ionic radii in chemistry
- Chemical bond-length measurements
- X-ray crystallography and wavelength measurements
History of the Angstrom
The angstrom is named after Anders Jonas Ångström (1814–1874), a Swedish physicist and one of the founders of spectroscopy, who used the unit in his 1868 atlas of the solar spectrum.
Historical origin. Angstrom was not the invention of a single named person; it developed through the process described above.
Astronomical unit — sources
- IAU Resolution B2 (2012) — Fixes the astronomical unit at exactly 149,597,870,700 meters.
Angstrom — sources
- NIST Guide to the SI, Appendix B — Lists the angstrom among non-SI units still in use with an exact SI equivalence.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many angstroms are in 1 astronomical unit?
1 astronomical unit equals 1.495979e+21 angstroms, using the exact defined conversion factor rather than an estimate.
How do I convert astronomical unit to angstrom?
Multiply the astronomical unit value by 1.495979e+21. The converter above does this instantly to whatever precision you set.
How do I convert angstrom back to astronomical unit?
Use the reverse factor: 1 angstrom equals 6.684587e-22 astronomical units. You can also use the swap control in the converter above to flip the direction instantly.
What is a astronomical unit?
Astronomical unit (AU) measures distance. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. It is classified as a Non-SI unit accepted for use with SI (astronomical).
What is a angstrom?
Angstrom (A) measures length. Equal to exactly 10⁻¹⁰ meters (0.1 nanometers) — a scale convenient for describing atomic radii, bond lengths, and crystal structures. It is classified as a non-SI unit, still common in chemistry and crystallography.
Is the astronomical unit to angstrom conversion exact?
Yes. Equal to exactly 10⁻¹⁰ meters (0.1 nanometers) — a scale convenient for describing atomic radii, bond lengths, and crystal structures. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the astronomical unit still used today?
Used internationally in astronomy for solar-system-scale distances.