Centimeters to Kilometers (cm to km)

1 centimeter equals 0.00001 kilometers exactly.

1 centimeter = 0.00001 kilometers

How to convert centimeters to kilometers

To convert centimeters to kilometers, multiply the number of centimeters by 0.00001. This factor is exact. To go the other way, multiply kilometers by 100,000.

kilometers = centimeters × 0.00001

Example: 10 centimeters = 0.0001 kilometers.

About these units

Centimeter (cm)

Metric (SI)Current unit

One hundredth of a meter. Used for body measurements, clothing and everyday objects.

Scientists, rather than shopkeepers, gave the centimeter its place. In 1832 Carl Friedrich Gauss proposed a system of absolute units built on length, mass and time, choosing the millimeter, milligram and second. In 1873 a committee of the British Association for the Advancement of Science, whose members included James Clerk Maxwell and William Thomson (Lord Kelvin), recommended the centimeter, gram and second instead. That CGS system dominated physics for decades, until the metre-kilogram-second system replaced it in the mid-twentieth century and led to SI.

CGS units proved awkward for rooms and buildings, which run to hundreds of centimeters, but the centimeter itself never went away. It is still the everyday unit for height, clothing and small objects, and it appears in map scales and rainfall reports. An adult fingernail is roughly one centimeter wide, and a milliliter is defined as exactly one cubic centimeter. An inch is exactly 2.54 centimeters. The CGS system itself survives mainly in theoretical physics and astrophysics, where Gaussian units are still common.

1 centimeter = 0.01 meters (exactly).

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

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

Related conversions

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