Convert miles to nautical miles

One mile equals 0.868976 nautical miles. To convert any number of miles to nautical miles, multiply by 0.86897624.

The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.

Length conversions come up wherever a measurement crosses a border: a height given in feet and inches on a form that wants centimetres, a running distance recorded in kilometres and compared against miles, a component specified in millimetres and ordered from a supplier working in inches. The conversions themselves are exact — the inch, foot, yard and mile have all been defined in metric terms since 1959 — so any discrepancy comes from rounding, not from the units disagreeing.

miles to nautical miles formula

To go the other way, use mile = nautical mile ÷ 0.86897624.

About these units

The statute mile is 5,280 feet — an awkward number inherited from the Roman mille passus of 1,000 paces, later adjusted to fit the English furlong.

A nautical mile is one minute of latitude, which is why it is the natural unit at sea and in the air. It was fixed at exactly 1,852 metres in 1929.

Mile is also written miles. Nautical Mile is also written nautical miles and nm.

Sources

1. National Bureau of Standards, "Refinement of Values for the Yard and the Pound", Federal Register, 1 July 1959 — the international yard as exactly 0.9144 m and the avoirdupois pound as exactly 0.45359237 kg.
2. International Hydrographic Conference, Monaco, 1929 — the international nautical mile as exactly 1,852 metres, from which the knot follows.