The international nautical mile is defined as exactly 1,852 meters. This converter therefore uses meters as its common base instead of chaining rounded conversion factors from one displayed unit to another.

The statute-mile value comes from dividing 1,852 m by the exact international mile definition of 1,609.344 m. The old 1.15078 factor was a rounded display value and should not be used internally as the conversion constant.

Nautical miles are closely associated with angular navigation, but the modern unit is a fixed length, not a latitude-dependent unit. Saying that one nautical mile “equals one minute of latitude everywhere” is too strong.

Earth is an oblate ellipsoid, so the physical length of one minute of geodetic latitude varies with latitude. The 1,852-meter international nautical mile was chosen as a convenient standardized length close to a minute of meridional arc. For ordinary chart work, the minute-of-latitude relationship remains a useful approximation.

Minutes of longitude behave differently: meridians converge toward the poles, so the east-west ground distance represented by one minute of longitude decreases strongly with latitude.

A nautical mile (nmi) is a distance. A knot (kn) is a speed equal to one nautical mile per hour. They should not be used interchangeably.

This calculator converts distance units only. It does not calculate travel time, groundspeed, current, wind correction, or route length.

Unit conversion can be mathematically exact even when the original distance measurement is not. For example, converting a charted or GPS-derived distance to eight decimal places does not make the source position or route accurate to eight decimal places.

The calculator keeps enough decimal precision to avoid unnecessary conversion rounding. For practical use, round the converted value to a precision appropriate for the source data and the navigation, reporting, or planning task.