An angstrom is 1e-10 meters.
Angstroms to Astronomical units Converter — A to AU
Convert Angstrom (A) to Astronomical unit (AU) using the exact conversion factor (1 angstrom = 6.684587e-22 astronomical unit). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Angstroms to Astronomical units 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 astronomical unit is the mean Earth-Sun distance.
Result = input x 1e-10 / 1.49597871e+11.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Angstroms to Astronomical units
Angstrom and Astronomical unit both measure length. Angstrom is typically associated with widely used internationally in chemistry, crystallography, and atomic/molecular physics, while Astronomical unit is typically associated with used internationally in astronomy for solar-system-scale distances..
Formula
astronomical units = angstroms × 6.684587e-22
This factor comes from each unit's defined relationship to the category's base unit: 1 angstrom equals 1e-10 base units, and 1 astronomical unit equals 149597870700 base units, so dividing one by the other gives the direct angstrom-to-astronomical unit factor of 6.684587e-22.
Simple example
1 A × 6.684587e-22 = 6.684587e-22 AU
1 angstrom = 6.684587e-22 astronomical units.
Real-world example
10 A × 6.684587e-22 = 6.684587e-21 AU
10 angstroms = 6.684587e-21 astronomical units.
Conversion table
| Angstrom (A) | Astronomical unit (AU) |
|---|---|
| 1 A | 6.684587e-22 AU |
| 5 A | 3.342294e-21 AU |
| 10 A | 6.684587e-21 AU |
| 21.0975 A | 1.410281e-20 AU |
| 42.195 A | 2.820562e-20 AU |
| 100 A | 6.684587e-20 AU |
Reverse conversion: Astronomical unit to Angstrom
6.684587e-22 AU × 1.495979e+21 = 0.9999999817 A
6.684587e-22 astronomical units = 0.9999999817 angstroms.
angstroms = astronomical units × 1.495979e+21
For a page dedicated to this direction, see Astronomical unit to Angstrom.
Angstrom vs. Astronomical unit
| Aspect | Angstrom | Astronomical unit |
|---|---|---|
| Family | non-SI unit, still common in chemistry and crystallography | Non-SI unit accepted for use with SI (astronomical) |
| Typical use | Atomic and ionic radii in chemistry | Measuring distances within the solar system (planetary orbits) |
| Where it's used | Widely used internationally in chemistry, crystallography, and atomic/molecular physics | Used internationally in astronomy for solar-system-scale distances. |
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.
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.
Angstrom — sources
- NIST Guide to the SI, Appendix B — Lists the angstrom among non-SI units still in use with an exact SI equivalence.
Astronomical unit — sources
- IAU Resolution B2 (2012) — Fixes the astronomical unit at exactly 149,597,870,700 meters.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many astronomical units are in 1 angstrom?
1 angstrom equals 6.684587e-22 astronomical units, using the exact defined conversion factor rather than an estimate.
How do I convert angstrom to astronomical unit?
Multiply the angstrom value by 6.684587e-22. The converter above does this instantly to whatever precision you set.
How do I convert astronomical unit back to angstrom?
Use the reverse factor: 1 astronomical unit equals 1.495979e+21 angstroms. You can also use the swap control in the converter above to flip the direction instantly.
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.
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).
Is the angstrom to astronomical unit conversion exact?
Yes. The astronomical unit is defined as exactly 149,597,870,700 meters, close to the average Earth-Sun distance. 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 angstrom still used today?
Widely used internationally in chemistry, crystallography, and atomic/molecular physics