Nautical Miles to Kilometers
Type a value in either box to convert between nautical miles and kilometers. The factor is 1.852.
| Nautical Miles | Kilometers |
|---|---|
| 1 nmi | 1.852 km |
| 2 nmi | 3.704 km |
| 3 nmi | 5.556 km |
| 5 nmi | 9.26 km |
| 10 nmi | 18.52 km |
| 25 nmi | 46.3 km |
| 50 nmi | 92.6 km |
| 100 nmi | 185.2 km |
How to use
- Enter a value in the Nautical Miles field.
- The Kilometers figure appears immediately — no button to press.
- Typing in the Kilometers field converts back to Nautical Miles the same way.
- Use the reference table for the values that come up most often.
Nautical Miles to Kilometers formula
The factor from nautical miles to kilometers is 1.852.
km = nmi × 1.852
Put another way, one nautical mile is exactly 463/250 kilometers.
Why this factor: the nautical mile and the kilometer are both defined against the meter, so dividing one definition by the other gives 1.852 directly. Both definitions are set out in full below.
To go the other way, divide by 1.852 — or use the Kilometers to Nautical Miles converter, which is the same calculation reversed.
Worked example
Given 100 nmi, multiplying by 1.852 yields 185.2 km.
100 nmi × 1.852 = 185.2 km
The converter above does this for any value you type, in either direction.
What is a nautical mile?
A nautical mile is the distance unit of sea and air navigation, chosen so it tracks latitude on a chart.
Definition: Exactly 1,852 meters, fixed by the 1929 International Extraordinary Hydrographic Conference. It approximates one arcminute of latitude.
Where it is used: Marine and aviation navigation, maritime boundaries, and the basis of the knot (one nautical mile per hour).
Worth knowing: About 15% longer than a statute mile — mixing the two is a classic navigation error.
What is a kilometer?
A kilometer is 1,000 meters, the standard unit for road distances and geography in most of the world.
Definition: Exactly 1,000 meters by SI prefix definition — 'kilo' means 10³.
Where it is used: Road signs, running and cycling distances, and map scales outside the US and UK.
Nautical Miles vs Kilometers
The nautical mile is a specialized unit while the kilometer is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many kilometers are in a nautical mile?
One nautical mile equals 1.852 kilometers.
What is the formula to convert nautical miles to kilometers?
Multiply the number of nautical miles by 1.852. To reverse it, divide by 1.852 instead.
How do I convert kilometers back to nautical miles?
Divide by 1.852, which is the same as multiplying by 0.539956803.
How many kilometers are in 10 nautical miles?
10 nmi works out to 18.52 km.
Is there anything to watch out for with nautical miles?
About 15% longer than a statute mile — mixing the two is a classic navigation error.
How is the nautical mile defined?
Exactly 1,852 meters, fixed by the 1929 International Extraordinary Hydrographic Conference. It approximates one arcminute of latitude.