Definition: The International System of Units uses the unit of length known as the kilometer (symbol: km) (SI). 0.6214 miles are equal to one kilometer.

Definition: A mile is a unit of length in the imperial and US customary systems of measurement (symbol: mi or m). Exactly 1,609.344 meters, or 5,280 feet, 1,760 yards, are the measurements used today.
The mile is still widely used in nations like the United States (US), United Kingdom (UK), Myanmar, and Liberia, as well as some other nations that are either US or UK territories or have historical ties with either country. This is despite the fact that most nations have switched to the metric system and now express land distance in kilometers rather than miles.

A mile is an imperial unit of measurement commonly used in the United States to determine the distance between two locations.
A kilometer is used to measure the same thing but is a metric unit of length.
Master the formula for converting kilometers to miles:
1 kilometer is equal to 0.621371 miles (often shortened to .62). 1 mile is equal to 1.609344 kilometers.
To convert kilometers to miles, simply multiply the number of kilometers by 0.62137.
For example:
Let's say you start with 5 kilometers. People are often interested in this conversion because they want to know how many miles are in a 5K run.
The formula is 5 X 0.62137= 3.1 miles.
Another way conversion read more here: