An angstrom is 1e-10 meters.
Angstroms to Kilometers Converter — A to km
Convert Angstrom (A) to Kilometer (km) using the exact conversion factor (1 angstrom = 1e-13 kilometer). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Angstroms to Kilometers 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.
Kilometer is 1000 meter units.
Result = input x 1e-10 / 1000.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Angstroms to Kilometers
Angstrom and Kilometer both measure length. Angstrom is typically associated with widely used internationally in chemistry, crystallography, and atomic/molecular physics, while Kilometer is typically associated with standard road, distance, and mapping unit in nearly every country except the United States.
Formula
kilometers = angstroms × 1e-13
This factor comes from each unit's defined relationship to the category's base unit: 1 angstrom equals 1e-10 base units, and 1 kilometer equals 1000 base units, so dividing one by the other gives the direct angstrom-to-kilometer factor of 1e-13.
Simple example
1 A × 1e-13 = 1e-13 km
1 angstrom = 1e-13 kilometers.
Real-world example
10 A × 1e-13 = 1e-12 km
10 angstroms = 1e-12 kilometers.
Conversion table
| Angstrom (A) | Kilometer (km) |
|---|---|
| 1 A | 1e-13 km |
| 5 A | 5e-13 km |
| 10 A | 1e-12 km |
| 21.0975 A | 2.10975e-12 km |
| 42.195 A | 4.2195e-12 km |
| 100 A | 1e-11 km |
Reverse conversion: Kilometer to Angstrom
1e-13 km × 1e+13 = 1 A
1e-13 kilometers = 1 angstrom.
angstroms = kilometers × 1e+13
For a page dedicated to this direction, see Kilometer to Angstrom.
Angstrom vs. Kilometer
| Aspect | Angstrom | Kilometer |
|---|---|---|
| Family | non-SI unit, still common in chemistry and crystallography | SI derived (metric prefix) unit |
| Typical use | Atomic and ionic radii in chemistry | Road signage, speed limits, and vehicle odometers outside the US |
| Where it's used | Widely used internationally in chemistry, crystallography, and atomic/molecular physics | Standard road, distance, and mapping unit in nearly every country except the United States |
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 Kilometer
Kilometer (km) measures distance. A kilometer is 1,000 meters — the meter is the SI base unit of length. It is classified as a SI derived (metric prefix) unit.
Where it's used: Standard road, distance, and mapping unit in nearly every country except the United States
Uses of the Kilometer today
- Road signage, speed limits, and vehicle odometers outside the US
- Geographic and mapping distances
- Endurance sports (marathons are measured in kilometers internationally, though the marathon distance itself is a fixed value in both systems)
History of the Kilometer
The meter was defined during the French Revolutionary metric reforms as one ten-millionth of the distance from the North Pole to the Equator along a meridian through Paris. 'Kilo-' is simply the SI prefix for 1,000, making the kilometer a direct decimal multiple.
The meter itself has been redefined several times as measurement precision improved — from a physical platinum-iridium bar (1889) to a krypton-86 wavelength (1960) to its current definition (1983) as the distance light travels in a fixed fraction of a second.
Historical origin. Kilometer 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.
Kilometer — sources
- BIPM — The metre (SI base unit) — Current definition and history of the meter.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kilometers are in 1 angstrom?
1 angstrom equals 1e-13 kilometers, using the exact defined conversion factor rather than an estimate.
How do I convert angstrom to kilometer?
Multiply the angstrom value by 1e-13. The converter above does this instantly to whatever precision you set.
How do I convert kilometer back to angstrom?
Use the reverse factor: 1 kilometer equals 1e+13 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 kilometer?
Kilometer (km) measures distance. A kilometer is 1,000 meters — the meter is the SI base unit of length. It is classified as a SI derived (metric prefix) unit.
Is the angstrom to kilometer 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 angstrom still used today?
Widely used internationally in chemistry, crystallography, and atomic/molecular physics