A kilometer is 1,000 meters. The prefix "kilo" always means one thousand, so the math never changes. Most of the world measures road distances and running races in kilometers, which is why road signs outside the United States and the United Kingdom count down in km.

It takes an average walker about 12 minutes to cover a kilometer, and a car on an open highway crosses one in well under a minute. A 5K race is five kilometers, and a marathon is a little over 42 kilometers.

In writing, the kilometer is usually shortened to "km". One kilometer is 1000 meters, and that ratio is what every figure on this page is built from.