The nautical mile is longer than a regular mile as it is based on the Earth's coordinates of longitude and latitude, with one nautical mile equal to one minute of latitude. When converted into familiar land measurements, a nautical unit of length equates to 1.15078 land miles or 1.852 kilometers. Nautical miles are used for charting and navigating.

Why is a nautical mile longer than a land mile?

<img src="https://oceanservice.noaa.gov/bs4/img/flag.png" alt="U.S. flag" width="25" height="17"><h2 dir="ltr">The nautical mile measures distance and the knot measures speed.</h2><figure><img src="https://oceanservice.noaa.gov/facts/NOAA-ship960.jpg" alt="Homeported in Pascagoula, Mississippi, NOAA Ship Pisces is the third in a class of state-of-the-art, acoustically quiet fisheries survey vessels built for a wide range of living marine resource surveys and ecosystem research projects. The ship focuses primarily on U.S. waters from the Gulf of Mexico, Caribbean, and South Atlantic to North Carolina." title="What is the difference between a nautical mile and a knot?" width="510" height="339"><figcaption dir="auto">The U.S. adopted the international nautical mile in 1954. Shown here: NOAA Ship Pisces is the third in a class of state-of-the-art, acoustically quiet fisheries survey vessels built for a wide range of living marine resource surveys and ecosystem research projects.</figcaption></figure><h2>Nautical Miles</h2>Nautical miles are used to measure the distance traveled through the water. A nautical mile is slightly longer than a mile on land, equaling <a href="https://oceanservice.noaa.gov/facts/nautical-mile-knot.html#" disabled="" dir="ltr">1.1508 land-measured (or statute) miles</a>. The nautical mile is based on the Earth’s longitude and latitude coordinates, with one nautical mile equaling one minute of latitude.But why use a different measurement system for marine navigation? Using latitude and longitude coordinates is more practical for long-distance travel, where the curvature of the Earth becomes a factor in accurate measurement. <a href="https://oceanservice.noaa.gov/facts/nautical_chart.html" dir="ltr">Nautical charts</a> use latitude and longitude, so it’s far easier for mariners to measure distance with nautical miles. Air and space travel also use latitude and longitude for navigation and nautical miles to measure distance.The word “mile” might leave you wondering if there’s a “nautical kilometer,” too. There’s not. The international nautical mile is used throughout the world. The measurement was officially set at exactly 1.852 kilometers in 1929 by what is now known as the <a href="https://iho.int/" dir="ltr">International Hydrographic Organization</a>. The U.S. and the United Kingdom both used slightly different measurements after that time, but the U.S. adopted the international nautical mile in 1954 and the U.K. in 1970.<h2>Knots</h2><figure><img src="https://oceanservice.noaa.gov/facts/knots.gif" alt="animation showing the measurement of a know in historical terms" title="What is the difference between a nautical mile and a knot?" width="140" height="157"><figcaption dir="auto">Measuring the knot in the 17th century.</figcaption></figure><a href="https://oceanservice.noaa.gov/education/tutorial_currents/06measure2.html" dir="ltr">Knots</a>, on the other hand, are used to measure speed. One knot equals one nautical mile per hour, or roughly <a href="https://oceanservice.noaa.gov/facts/nautical-mile-knot.html#" disabled="" dir="ltr">1.15 statute mph</a>.The term knot dates from the 17th century, when sailors measured the speed of their ship using a device called a “common log.” The common log was a rope with knots at regular intervals, attached to a piece of wood shaped like a slice of pie. Mariners would lower the wood piece into the water and allow it to float freely behind the ship for a specific amount of time (often measured with an hourglass). When the time was up, they would count the knots between the ship and the piece of wood, and that number estimated their speed.<img src="https://oceanservice.noaa.gov/facts/nautical_chart-small.jpg" alt="an electronic nautical chart screenshot" width="96" height="64"><h5>Did you know?</h5> You can create your own paper and PDF nautical charts with <a href="https://devgis.charttools.noaa.gov/pod/" dir="ltr">NOAA Custom Charts</a>. It’s easy to zoom in and explore NOAA’s 3.2 million square nautical miles of charts. Select your area of interest and the scale you’d like to use, then download a printable digital copy.

Nautical miles are used to measure the distance traveled through the water. A nautical mile is slightly longer than a mile on land, equaling 1.1508 land-measured (or statute) miles (1.852 kilometers). The nautical mile is based on the Earth’s longitude and latitude coordinates, with one nautical mile equaling one minute of latitude. Knots are used to measure speed.

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The nautical mile measures  distance  and the knot measures  speed  .

Nautical miles are used to measure the distance traveled through the water. A nautical mile is slightly longer than a mile on land, equaling <a href="https://oceanservice.noaa.gov/facts/nautical-mile-knot.html#">1.1508 land-measured (or statute) miles </a> . The nautical mile is based on the Earth’s longitude and latitude coordinates, with one nautical mile equaling one minute of latitude.

But why use a different measurement system for marine navigation? Using latitude and longitude coordinates is more practical for long-distance travel, where the curvature of the Earth becomes a factor in accurate measurement. <a href="https://oceanservice.noaa.gov/facts/nautical_chart.html">Nautical charts </a>use latitude and longitude, so it’s far easier for mariners to measure distance with nautical miles. Air and space travel also use latitude and longitude for navigation and nautical miles to measure distance.

The word “mile” might leave you wondering if there’s a “nautical kilometer,” too. There’s not. The international nautical mile is used throughout the world. The measurement was officially set at exactly 1.852 kilometers in 1929 by what is now known as the <a href="https://iho.int/">International Hydrographic Organization </a>. The U.S. and the United Kingdom both used slightly different measurements after that time, but the U.S. adopted the international nautical mile in 1954 and the U.K. in 1970.

<a href="https://oceanservice.noaa.gov/education/tutorial_currents/06measure2.html">Knots </a>, on the other hand, are used to measure speed. One knot equals one nautical mile per hour, or roughly <a href="https://oceanservice.noaa.gov/facts/nautical-mile-knot.html#">1.15 statute mph </a> .

The term knot dates from the 17th century, when sailors measured the speed of their ship using a device called a “common log.” The common log was a rope with knots at regular intervals, attached to a piece of wood shaped like a slice of pie. Mariners would lower the wood piece into the water and allow it to float freely behind the ship for a specific amount of time (often measured with an hourglass). When the time was up, they would count the knots between the ship and the piece of wood, and that number estimated their speed.

You can create your own paper and PDF nautical charts with <a href="https://devgis.charttools.noaa.gov/pod/">NOAA Custom Charts </a>. It’s easy to zoom in and explore NOAA’s 3.2 million square nautical miles of charts. Select your area of interest and the scale you’d like to use, then download a printable digital copy.

What is the difference between a nautical mile and a knot?

Why is a nautical mile longer than a land mile?

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