What is kilometre?
A kilometre is a metric unit of length equal to 1,000 metres. It is the standard unit for road distances, route planning, and geographic measurements in most countries.
Real-world uses
Kilometres are the standard unit for road distances, city-to-city navigation, and speed limits in most countries outside the United States. Marathon runners track their pace in minutes per kilometre, and GPS devices report distances in km.
History
Introduced as part of the metric system in France in 1795. The prefix "kilo-" comes from the Greek word "chilioi" meaning thousand. It became the global standard for road distances as the metric system spread in the 19th and 20th centuries.
Common mistakes
Assuming 1 mile equals 1 kilometre—a mile is actually about 1.609 km. Another error is mispronouncing it as "kil-AH-meter" instead of "KIL-o-metre," which changes the implied meaning.
What is metre?
The metre is the SI base unit of length. It is used globally in science, engineering, geography, and everyday measurement as the standard reference for distance.
Real-world uses
The metre is the standard unit for everyday measurements worldwide, from room dimensions and furniture sizes to athletic track events like the 100 m sprint. Engineers, architects, and scientists use it as the fundamental length reference in the SI system.
History
Originally defined in 1793 during the French Revolution as one ten-millionth of the distance from the North Pole to the equator along a meridian through Paris. Since 1983, it is defined by the speed of light in vacuum.
Common mistakes
Confusing "meter" (the measuring device) with "metre" (the unit of length) in British English. Also, people sometimes incorrectly assume 1 metre equals exactly 3 feet; it is actually about 3.281 feet.
When is this conversion used?
This conversion is frequently needed in construction, architecture, and real estate where building codes may specify dimensions in one system while materials are sold in another. Road distances and speed limits are posted in kilometres in most countries and miles in the US and UK, making this conversion essential for international drivers and route planning.
Worked examples
1 kilometre = 1,000 metre
1 metre = 1 metre
How to convert kilometre to metre
To convert kilometre to metre, multiply the value by 1,000.
To convert metre back to kilometre, multiply by 0.001.
Measurement standards
The metre is one of seven SI base units, maintained by the International Bureau of Weights and Measures (BIPM). Since 2019, it is defined by fixing the numerical value of the speed of light in vacuum to exactly 299,792,458 metres per second.
Did you know?
A human hair is roughly 70 micrometres wide, while a single gold atom measures about 0.144 nanometres in diameter — meaning you could line up nearly half a million atoms across the width of one hair.
Quick reference: kilometre to metre
| kilometre | metre |
|---|---|
| 0.1 | 100 |
| 0.5 | 500 |
| 1 | 1,000 |
| 2 | 2,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
| 250 | 250,000 |
| 500 | 500,000 |
| 1,000 | 1,000,000 |
Common values
| kilometre | metre | |
|---|---|---|
| Height of a door | 0.0021 kilometre | 2.1 metre |
| Basketball court length | 0.028 kilometre | 28 metre |
| Football field (soccer) | 0.105 kilometre | 105 metre |
| Marathon distance | 42.195 kilometre | 42,195 metre |
| Altitude of a cruising airplane | 10.668 kilometre | 10,668 metre |