Inches to Nautical Miles (in to nmi)

1 inch equals 0.00001371490281 nautical miles (rounded).

1 inch = 0.00001371490281 nautical miles

How to convert inches to nautical miles

To convert inches to nautical miles, multiply the number of inches by 0.00001371490281. The factor is rounded to 10 significant digits. To go the other way, multiply nautical miles by 72,913.38583 (rounded).

nautical miles = inches × 0.00001371490281

Example: 10 inches = 0.0001371490281 nautical miles.

About these units

Inch (in)

US & ImperialCurrent unit

1/12 of a foot. Defined as exactly 25.4 millimeters since 1959, when the US and Commonwealth countries agreed a common international inch.

Latin uncia, meaning one-twelfth, is the root of both inch and ounce, and it passed into Old English as ynce. Roman measurers divided their foot into twelve unciae, and the English inch kept that twelfth. After 1066 an inch was reckoned as three barleycorns, and a 1324 statute attributed to Edward II spelled out the definition as three grains of barley, dry and round, placed end to end lengthwise. For centuries the inch was simply a twelfth of a foot, or a thirty-sixth of a yard, and the US and UK each kept their own copy of the standard yard.

Those copies differed slightly until the 1959 international agreement fixed the yard at exactly 0.9144 meter, which made the inch exactly 25.4 millimeters. The US adopted it in 1959 and the UK ratified it in 1963, effective 1964. Today the inch is still the customary unit in the United States and Canada, and the UK keeps it on road signs. Worldwide it also names display diagonals, wheel rims, tire codes and pipe sizes.

1 inch = 0.0254 meters (exactly).

Sources: Wikipedia: Inch; Wikipedia: Yard; 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

See all length units.