Convert Angstrom to Kilometer (Å → km)

Converting angstroms to kilometers is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in angstroms

   Start with the number of angstroms (Å) you want to convert.
2. 2
   Multiply by 1 × 10^-13

   The conversion factor from Å to km is 1 × 10^-13. Multiply your value by this number.
3. 3
   Read the result in kilometers

   The result is your value in kilometers (km).

Multiply the value in angstroms by 1 × 10^-13. For the reverse direction, multiply by 10,000,000,000,000.

• ✓1 Å = 0.1 nm = 100 pm. Modern SI recommends nm or pm for new publications.
• ✓The ångström is named after the Swedish physicist Anders Jonas Ångström.
• ✓For quick atomic-scale intuition: most atoms are 1–3 Å across.

• ✗Mixing up Å with µm — the scale differs by 10,000×.
• ✗Using Å for anything macroscopic — always use nm or mm for things visible under a light microscope.
• ✗Forgetting the diacritic in "Ångström" — the symbol Å avoids spelling issues.

What is the Angstrom?

The angstrom equals exactly 0.1 nanometers or 10⁻¹⁰ meters and is the historical unit for atomic and molecular dimensions. Named after Swedish physicist Anders Jonas Ångström (1814–1874), who used it to chart the wavelengths of solar spectral lines, the unit was widely adopted in spectroscopy, crystallography, and chemistry. The diameter of a hydrogen atom is about 1 Å, and visible light wavelengths range from 4,000 to 7,000 Å. While the SI system officially recommends nanometers (10 Å = 1 nm), the angstrom remains common in older physics and chemistry literature, X-ray diffraction studies, and crystal structure data. The symbol Å uses a special character with a circle above the A. The angstrom is one of the few non-SI units still routinely used in scientific publications, particularly in solid-state physics.

• X-ray crystallography and protein structure
• Chemical bond length measurement
• Atomic physics and spectroscopy

What is the Kilometer?

The kilometer equals exactly 1,000 meters and is the international standard unit for road distances, geography, and travel. Adopted as part of the metric system in the 1790s, it became the dominant road-distance unit worldwide except in the United States, the United Kingdom (which uses miles for road signs), and Myanmar. Speed limits across Europe, Asia, Australia, Africa, and Latin America are expressed in km/h. The kilometer's relationship to the meter is decimal and exact, making it ideal for scientific work. A kilometer takes a healthy adult about 12 minutes to walk and roughly 1,250 average steps. Geographic distances — from city blocks to airline routes — are typically given in kilometers, with the Earth's equatorial circumference measuring approximately 40,075 km.

• Motorway distances on road signs across Europe
• Marathon and long-distance running (marathon = 42.195 km)
• GPS navigation and driving directions globally