Convert nautical miles to common distance units or calculate voyage time from distance and speed in knots.

Nautical Mile Formula

The following relationships can be used to convert between nautical miles, statute miles, and kilometers.

1~NM \approx 1.15078~mi

Where NM is a nautical mile
mi is a statute mile (mile)

1~NM = 1.852~km

Where NM is a nautical mile
km is kilometres

To convert international statute miles to nautical miles, multiply by the defined ratio 1609.344 / 1852. Dividing by 1.15078 or multiplying by 0.868976 gives a rounded approximation.

Nautical Mile Definition

A nautical mile is a unit of distance used in marine and air navigation. It is defined as exactly 1,852 meters (1.852 km), which is approximately one minute of latitude (one minute of arc along a meridian). This is about 1.15078 statute miles.

A knot is a unit of speed equal to one nautical mile per hour, so traveling at 1 knot for 1 hour covers 1 nautical mile. Estimated voyage time in hours is route distance in nautical miles divided by average speed over ground in knots, excluding stops and changing conditions.

Both knots and nautical miles are commonly used in maritime navigation and aviation. Since ships and aircraft travel great distances, using standard units tied to Earth-based navigation helps standardize distance and speed measurements.

Nautical Mile Example

How to calculate a nautical mile?

First, measure the direct distance.
Measure the direct distance in miles or kilometers.
Next, convert to nautical miles.
Using the formulas above, calculate the nautical miles.

FAQ

nautical mile formula — The statute-mile value in this graphic is rounded. Here M means an international statute mile; 1 nautical mile is exactly 1,852 meters.