Convert Length from Miles to Kilometers (mi to km)

What is a Mile (mi)?

A mile (mi) is a common unit of length used in the imperial and US customary systems of measurement.

The official definition of a mile is 5,280 feet (ft). The plural form is miles.

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Where Did the Word "Mile" Come From?

The word "mile" has ancient roots, originating from the Latin phrase "mille passus," which translates to "a thousand paces."

In ancient Rome, one pace was measured as two steps (one left and one right). The Roman mile was therefore 1,000 paces, which equals approximately 4,850 feet—slightly shorter than the modern mile.

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What's the Difference Between a Statute Mile and a Nautical Mile?

Not all miles are created equal. While most people are familiar with the land mile, there is also a separate measurement used for air and sea travel.

The Statute Mile (Land Mile)

The commonly used mile on land is the statute mile, which is officially defined as 5,280 feet. This measurement is used for driving distances and most other land-based activities in the imperial system.

The Nautical Mile (Air and Sea)

The nautical mile is used for navigation in aviation and maritime settings. It is based on the Earth's circumference and is equal to one minute of arc of latitude. A nautical mile is longer than a statute mile.

Here's a quick comparison:

• 1 Statute Mile = 5,280 feet
• 1 Nautical Mile = approximately 6,076 feet (or about 1.15 statute miles)

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Why Are There 5,280 Feet in a Mile?

The seemingly random number of 5,280 feet in a mile comes from English history. In 1593, the English Parliament, under Queen Elizabeth I, passed a statute to standardize units of measurement.

The statute defined the official length of a mile as being equal to 8 furlongs. Since one furlong was already established as 660 feet, the calculation was simple:

• 8 furlongs × 660 feet = 5,280 feet

This decision solidified the length of the statute mile that we still use today in countries that follow the imperial system.

What is a Kilometer (km)?

A kilometer (km) is a unit of length in the metric system, equal to 1,000 meters.

The plural form is kilometers.

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Where Does the Word "Kilometer" Come From?

The term "kilometer" is composed of two parts: the metric unit "meter" and the Greek prefix "kilo," which comes from the word "khilioi," meaning "thousand."

Thus, a kilometer translates to one thousand meters.

This concept is a fundamental aspect of the decimal-based metric system, established in France during the 1790s. The logical, prefix-based nature of the metric system simplifies conversions, which is a key reason for its widespread adoption.

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Which Countries Use the Kilometer?

The kilometer is the official unit of measurement for geographical distance in the vast majority of countries worldwide.

Only a few nations still primarily use the mile for road signage and navigation, most notably:

• The United States
• The United Kingdom
• Liberia
• Myanmar

For international travel, science, and sporting events like marathons and the Olympics, the kilometer is the universally accepted standard.

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How Far Is a Kilometer? Examples You Can Visualize

To understand how far a kilometer is, consider these real-world examples:

• Walking one kilometer at an average pace takes about 10 to 12 minutes.
• The Earth's circumference at the equator is approximately 40,075 kilometers.
• In terms of astronomical distances, the Moon is, on average, about 384,400 kilometers away from Earth.

This consistent unit of measurement makes it easy to compare everything from everyday travel to distances in space.