Kilometers to Nautical Miles
Type a value in either box to convert between kilometers and nautical miles. The factor is 0.539957.
| Kilometers | Nautical Miles |
|---|---|
| 1 km | 0.539957 nmi |
| 2 km | 1.079914 nmi |
| 3 km | 1.61987 nmi |
| 5 km | 2.699784 nmi |
| 10 km | 5.399568 nmi |
| 25 km | 13.49892 nmi |
| 50 km | 26.99784 nmi |
| 100 km | 53.99568 nmi |
How to use
- Enter a value in the Kilometers field.
- The Nautical Miles figure appears immediately — no button to press.
- Typing in the Nautical Miles field converts back to Kilometers the same way.
- Use the reference table for the values that come up most often.
Kilometers to Nautical Miles formula
The factor from kilometers to nautical miles is 0.539956803.
nmi = km × 0.539956803
Put another way, one kilometer is exactly 250/463 nautical miles.
Why this factor: the kilometer and the nautical mile are both defined against the meter, so dividing one definition by the other gives 0.539956803 directly. Both definitions are set out in full below.
To go the other way, divide by 0.539956803 — or use the Nautical Miles to Kilometers converter, which is the same calculation reversed.
Worked example
Given 100 km, multiplying by 0.539956803 yields 53.99568 nmi.
100 km × 0.539956803 = 53.99568 nmi
The converter above does this for any value you type, in either direction.
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.
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.
Kilometers vs Nautical Miles
The kilometer is a metric unit while the nautical mile is a specialized 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 nautical miles are in a kilometer?
One kilometer equals 0.539956803 nautical miles.
What is the formula to convert kilometers to nautical miles?
Multiply the number of kilometers by 0.539956803. To reverse it, divide by 0.539956803 instead.
How do I convert nautical miles back to kilometers?
Divide by 0.539956803, which is the same as multiplying by 1.852.
How many nautical miles are in 10 kilometers?
10 km works out to 5.399568 nmi.
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 kilometer defined?
Exactly 1,000 meters by SI prefix definition — 'kilo' means 10³.