What Is a Nautical Mile (nmi)?
Definition
Nautical Mile (nmi): A unit of length used at sea and in aviation, symbol nmi. The international nautical mile is exactly 1,852 meters, longer than the 1,609.344-meter international mile.
The nautical mile (symbol nmi) is a unit of length used at sea and in the air. The international nautical mile is exactly 1,852 meters. Its size was chosen to be close to one minute of latitude, which makes distances easy to read on charts. A speed of one nautical mile per hour is called a knot.
Where it appears in the formulas
1 nmi = 1,852 m = 1.852 km. The length converter uses this exact value (NIST SP 811, Appendix B). For example, 10 nautical miles is 18.52 km, and 1 nautical mile is about 1.1508 miles.
Not the same as a mile
The international mile is 1,609.344 meters. One kilometer is about 0.54 nautical miles or 0.6214 miles.