Kilometers to Angstroms (km to Å)

1 kilometer equals 10,000,000,000,000 angstroms exactly.

1 kilometer = 10,000,000,000,000 angstroms

How to convert kilometers to angstroms

To convert kilometers to angstroms, multiply the number of kilometers by 10,000,000,000,000. This factor is exact. To go the other way, multiply angstroms by 1×10⁻¹³.

angstroms = kilometers × 10,000,000,000,000

Example: 10 kilometers = 100,000,000,000,000 angstroms.

About these units

Kilometer (km)

Metric (SI)Current unit

1,000 meters. The standard unit for road distances in most countries.

A name for 1,000 meters took a while to settle. In 1793 France's National Convention made the metre the sole French unit of length, and the first proposed name for the thousand-metre multiple was millaire. Everyday French usage then leaned on the myriametre, 10,000 meters, well into the 1800s. The Netherlands adopted the kilometre in 1817, under the local name mijl, and made it the only official unit of that size in 1867. In 1935 the CIPM dropped the myria- prefix, which left the kilometre as the standard unit for road-scale distances.

Kilo- is the SI prefix for a thousand, and the kilometre is now the preferred unit for land distances in most of the world, with the United States, the United Kingdom and Liberia among those that still use the mile. One kilometre is about 0.621 mile. The main span of Lisbon's 25 de Abril Bridge, at 1.013 km, gives a sense of the scale. Even its pronunciation has been argued over: in 1970 Australia's Metric Conversion Board made stress on the first syllable official, although Prime Minister Gough Whitlam argued for stress on the second. Military slang in several countries calls it a klick.

1 kilometer = 1,000 meters (exactly).

Sources: Wikipedia: Kilometre; Wikipedia: Metric prefix; BIPM: history of the metre

Angstrom (Å)

ScientificTraditional unit (still used in some regions)

One ten-billionth of a meter (0.1 nm). Named after Anders Ångström and used for atomic and molecular sizes and bond lengths.

Swedish physicist Anders Jonas Angstrom (1814-1874) charted the solar spectrum in 1868 in multiples of one ten-millionth of a millimeter, and solar physicists later named that interval after him. It equals 10 to the minus 10 meter, 0.1 nanometer or 100 picometers. Atoms and bonds fit it well: hydrogen is about 0.5 angstrom in covalent radius, and visible light spans roughly 4000 to 7000 angstroms.

The unit's size was not always exact. In 1907 the International Angstrom was fixed as 1/6438.4696 of the cadmium red line wavelength, a definition the 7th CGPM endorsed in 1927. The 1960 redefinition of the meter by a spectral line made it exactly 10 to the minus 10 meter, and NIST lists the conversion as exact. A later X-ray version, the angstrom star of 1965, was obsolete within about ten years. The unit was listed as acceptable by NIST and BIPM until 2019 but is absent from the 9th SI Brochure, and nanometers and picometers are slowly replacing it.

1 angstrom = 1×10⁻¹⁰ meters (exactly).

Sources: Wikipedia: Angstrom; NIST Guide to the SI, Appendix B.8; Wikipedia: Picometre

Related conversions

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