Feet to Miles Converter

The foot is exactly 0.3048 meters, or twelve inches. United States survey work has used a separate survey foot, defined as 1200/3937 meters and equal to about 0.3048006 meters.

Aviation uses feet for altitude and flight levels worldwide, even in countries that measure road distance in kilometers. Building heights, room dimensions, timber and, in some places, body height are also quoted in feet.

The metric conversion is exact, since the foot is defined as 0.3048 meters, and the reverse is exact too. A displayed result is rounded to six decimal places at most, so a round trip can differ in the final digit.

The common slip is assuming a foot is close to a third of a meter when it is slightly longer, so rough mental division undershoots. Feet also belong to length, while square feet measure area and cubic feet measure volume.

The foot competes with the meter for height and building dimensions and with the inch for small spans. Because one meter is a little over three feet, treating a meter figure as feet overstates a dimension more than threefold.

The international mile is exactly 1,609.344 meters, or 1.609344 kilometers. It descends from the Roman mile of a thousand paces and remains the standard road distance in the United States and the United Kingdom.

Road signs and speed limits, distance markers on highways, running and cycling events and aviation track distances are quoted in miles in those countries. Nautical miles are separate and longer.

Since the mile is defined as 1,609.344 meters exactly, converting to kilometers or feet is exact arithmetic; only the printed result is rounded. A value converted to kilometers and back can return with a changed last digit.

The common error is using a statute mile where a nautical mile is meant, which understates the intended distance by about thirteen percent. Miles also measure length, not area or speed.

Miles measure road distance, kilometers do the same on metric roads, and nautical miles measure sea and air distance. A nautical mile is longer than a statute mile, so a flight quoted in the wrong one is misread by roughly thirteen percent.