Millimeters to Angstroms (mm to Å)

1 millimeter equals 10,000,000 angstroms exactly.

1 millimeter = 10,000,000 angstroms

How to convert millimeters to angstroms

To convert millimeters to angstroms, multiply the number of millimeters by 10,000,000. This factor is exact. To go the other way, multiply angstroms by 1×10⁻⁷.

angstroms = millimeters × 10,000,000

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

About these units

Millimeter (mm)

Metric (SI)Current unit

One thousandth of a meter. Used in engineering, manufacturing and rainfall measurement.

Carl Friedrich Gauss put the millimeter at the base of his 1832 proposal for absolute units, pairing it with the milligram and the second, although the centimeter-based CGS system later won out among scientists. The name combines the metric prefix milli-, from the Latin for one thousand, with the meter. Since 1983 a millimeter has been tied to the speed of light: it is the distance light covers in 1/299,792,458,000 of a second.

Millimeters are the language of fine mechanical work. Standard rulers are divided into them, digital calipers commonly read to 0.01 mm, and mechanical pencil leads come in 0.5 and 0.7 mm. Copy paper is about 0.1 mm thick, and a thin hair, at 0.02 to 0.04 mm across, is close to the smallest thing the naked eye can see. A wave with a frequency of 300 GHz has a wavelength of 1 mm. An inch is exactly 25.4 mm. One trap for readers in the United States is that mil there traditionally means a thousandth of an inch, not a millimeter.

1 millimeter = 0.001 meters (exactly).

Sources: Wikipedia: Millimetre; Wikipedia: Centimetre-gram-second system of units; NIST Guide to the SI, Appendix B.8: conversion factors

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

See all length units.