Feet to Nautical Miles (ft to nmi)

1 foot equals 0.0001645788337 nautical miles (rounded).

1 foot = 0.0001645788337 nautical miles

How to convert feet to nautical miles

To convert feet to nautical miles, multiply the number of feet by 0.0001645788337. The factor is rounded to 10 significant digits. To go the other way, multiply nautical miles by 6,076.115486 (rounded).

nautical miles = feet × 0.0001645788337

Example: 10 feet = 0.001645788337 nautical miles.

About these units

Foot (ft)

US & ImperialCurrent unit

12 inches. Defined as exactly 0.3048 meters. Still the standard unit for height, altitude in aviation and room dimensions in the US and UK.

Human anatomy supplied the idea: an adult foot is roughly 15 percent of body height. Ancient cultures turned that into standards, but not the same one. The Greek pous was about 302 mm, the standard Roman pes about 295.7 mm, and a Harappan foot of about 335 mm has been reported from the Indus Valley. Historically, a foot fell somewhere between about 250 and 335 mm. Charlemagne tried to standardize units around 790 with little lasting success, and in 1593 English law fixed the statute mile at 5,280 feet.

The modern foot dates from the 1959 International Yard and Pound Agreement, which defined the yard as exactly 0.9144 meter and so the foot as exactly 0.3048 meter; the UK adopted it on 1 January 1964. The US survey foot, defined in 1893 as 1200/3937 meter, was deprecated on 31 December 2022. Feet remain in everyday use for height and rooms in the US, and ISO shipping containers are defined in them. Aviation altitudes use them too: flight level 330 means 33,000 feet.

1 foot = 0.3048 meters (exactly).

Sources: Wikipedia: Foot (unit); Wikipedia: Mile; NIST Guide to the SI, Appendix B.8: conversion factors

Nautical Mile (nmi)

NauticalCurrent unit

Exactly 1,852 meters, close to one minute of latitude. The standard unit of distance at sea and in aviation; one nautical mile per hour is one knot.

Sailors wanted a distance that matched their charts, so the nautical mile was tied to the globe itself: one minute of arc, one sixtieth of a degree, of latitude. Earth's polar circumference is therefore close to 21,600 nautical miles. Because Earth is flattened at the poles, a minute of latitude is about 1,843 meters at the equator and about 1,862 at the poles, so the fixed value of 1,852 meters is a compromise. France's definition of the meter produced a figure near 1,851.85 meters, which helped set the number.

The First International Extraordinary Hydrographic Conference in Monaco defined the international nautical mile as exactly 1,852 meters in 1929. The United States kept its own variant until 1954, and the United Kingdom adopted the international value in 1970. A speed of one nautical mile per hour is one knot. The unit is not part of SI but remains the norm in air, marine and space navigation and in defining territorial waters, because distances on a chart can be read straight off the latitude scale. Its symbols vary: NM, nmi and M all appear.

1 nautical mile = 1,852 meters (exactly).

Sources: Wikipedia: Nautical mile; NIST Guide to the SI, Appendix B.8: conversion factors

Related conversions

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