Kilometers to Nanometers (km to nm)

1 kilometer equals 1,000,000,000,000 nanometers exactly.

1 kilometer = 1,000,000,000,000 nanometers

How to convert kilometers to nanometers

To convert kilometers to nanometers, multiply the number of kilometers by 1,000,000,000,000. This factor is exact. To go the other way, multiply nanometers by 1×10⁻¹².

nanometers = kilometers × 1,000,000,000,000

Example: 10 kilometers = 10,000,000,000,000 nanometers.

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

Nanometer (nm)

Metric (SI)Current unit

One billionth of a meter. Used for the wavelength of light (visible light is about 400–700 nm) and for chip feature sizes.

Greek for dwarf gave nano- its name, and the nanometer was once called something clumsier: the millimicrometre, or more often the millimicron, written mμ, since it is a thousandth of a micrometer. The prefix nano- was among those officially adopted when SI prefixes were first introduced in 1960, and the nanometer grew into the standard unit for optics and microelectronics. It sits a factor of ten above the older ångström, which is 0.1 nm and is still used for atomic distances.

Visible light spans roughly 400 to 700 nm, which is why color and spectroscopy are quoted this way. A helium atom is about 0.06 nm across and a ribosome about 20 nm. Chip makers have used nanometers since the late 1980s in names for manufacturing generations such as 32 nm and 22 nm. Those are labels for successive generations in the industry roadmap, and they describe typical feature sizes rather than one exact measurement. Readers should also beware that nm is sometimes written informally for the nautical mile.

1 nanometer = 1×10⁻⁹ meters (exactly).

Sources: Wikipedia: Nanometre; Wikipedia: Metric prefix; Wikipedia: Nautical mile

Related conversions

See all length units.