How long is a nautical knot as compared to land miles?

Measuring Distance:
Distance at sea is measured in nautical miles as opposed to statute (land) miles. The international nautical mile is equal to 1/60 of one degree of the earth's circumference.


Nautical Miles = Statute Miles
1 = 1.151
5 = 5.755


Measuring Speed:
Nautical speed for ships and airplanes is measured in knots. One knot is equal to one nautical mile per hour.

Knots = Miles per hour
10 = 11.51
20 = 23.02

Just to amplify Koz's excellent explanation, a nautical mile is 6080 feet as against 5280 feet for a statute mile.

A quick rule of thumb approximation is that 7 nautical miles = 8 statute miles, or 7 knots = 8 m.p.h. (actually 8.06).

Just to add a bit of trivia to Koz and Ewood's correct answers; a nautical mile is one minute of arc measured at the equator.
Oops, sorry. I just realized that Koz had already said the same thing in slightly different words.

In actual use, a nautical mile is 2000 meters.

mahal - I'm interested in who uses 2000 meters for a nautical mile as that is significantly different than the 1852 meters that I have always seen.

This is the standard used by the US Navy and Coast Guard, and in fact all of our equipment is based on this distance.

For example a radar mile is 12.58 microseconds. A radar signal, traveling at the speed of light, will cover 2000 meters in 6.29 microseconds and echo back in the same time. (A radar mile is the round trip, not the distance to the target.)

mahal - thanks