If you've ever wondered why a mile at sea is longer than a mile on land, the answer lies in the geometry of the Earth.

The Statute Mile

The classic mile (statute mile) is 1,609 meters and is based on the ancient Roman tradition of 1,000 paces.

The Nautical Mile

The nautical mile is 1,852 meters and is based on the circumference of the Earth. It corresponds to "one minute of arc" (1/60 of a degree) of latitude. This makes it extremely useful for navigation with maps.