Nautical Miles to Kilometers
Convert nautical mile to kilometer instantly — type a value and read the result, with the exact formula shown.
Reviewed by the CalcCafe editorial team · Last updated 1 July 2026 · How we test our tools
Example
1 nmi = 1.852 km, 5 nmi = 9.26 km, 10 nmi = 18.52 km.
Common conversions: nautical mile to kilometer
Quick reference for the nmi → km values you are most likely to need, computed with the exact factor the converter above uses. It includes the specific values people most often look up (10 nmi, 12 nmi, 200 nmi, 100 nmi, 1,000 nmi).
| Nautical mile (nmi) | Kilometer (km) |
|---|
| 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 |
| 12 nmi | 22.224 km |
| 15 nmi | 27.78 km |
| 20 nmi | 37.04 km |
| 25 nmi | 46.3 km |
| 30 nmi | 55.56 km |
| 40 nmi | 74.08 km |
| 50 nmi | 92.6 km |
| 60 nmi | 111.12 km |
| 70 nmi | 129.64 km |
| 75 nmi | 138.9 km |
| 80 nmi | 148.16 km |
| 90 nmi | 166.68 km |
| 100 nmi | 185.2 km |
| 150 nmi | 277.8 km |
| 200 nmi | 370.4 km |
| 250 nmi | 463 km |
| 500 nmi | 926 km |
| 1,000 nmi | 1,852 km |
Kilometer to Nautical mile
| Kilometer (km) | Nautical mile (nmi) |
|---|
| 1 km | 0.539957 nmi |
| 5 km | 2.6998 nmi |
| 10 km | 5.3996 nmi |
| 50 km | 26.9978 nmi |
| 100 km | 53.9957 nmi |
How it works
Kilometer = Nautical mile × 1.852. Every value is converted through a single meter base unit using internationally defined conversion factors, so any from/to pair stays consistent.
Good to know
Nautical miles are the standard distance unit for travel at sea and in the air, so converting them to kilometers is something sailors, pilots, divers, and offshore racers do constantly when comparing a chart distance against a road map, a fuel calculation, or a weather report given in metric. If a marine forecast says a vessel is 30 nmi offshore, that is 55.56 km — a useful translation when most land-based tools, GPS units, and emergency services speak in kilometers.
The two units come from completely different origins. The kilometer is a metric unit defined from the meter, which today is fixed by the speed of light. The nautical mile is geographic: it was historically one minute of arc of latitude along a meridian, which is why it ties so neatly to navigation charts. In 1929 it was standardized to exactly 1,852 meters, making 1 nmi = 1.852 km an exact figure rather than an approximation.
A quick mental shortcut: nautical miles are a little under twice the kilometers, so to estimate kilometers from nautical miles, double the value and shave off about 7 to 8 percent. For 40 nmi, double to 80, drop roughly 6, and you land near 74 km (the exact answer is 74.08 km). For rougher work, "add about 85 percent" also gets you close.
The most common mistake is confusing the nautical mile with the ordinary statute mile of 1.609 km. They are not interchangeable: a nautical mile is roughly 15 percent longer. Mixing them up in a speed or distance calculation is also where knots get muddled, since one knot is one nautical mile per hour (1.852 km/h), not one statute mile per hour.
Frequently asked questions
How do you convert nautical mile to kilometer?
Multiply the number of nautical miles by 1.852 to get kilometers. For example, 1 nmi = 1.852 km.
What is 1 nautical mile in kilometers?
1 nautical mile equals 1.852 kilometers (1 nmi = 1.852 km).
How many nautical miles are in 1 kilometer?
There are 0.5399568 nautical miles in 1 kilometer.
Is this converter free and private?
Yes. It runs entirely in your browser, so your inputs never leave your device, there is no sign-up, and it works offline once loaded.
Are the conversions exact?
Conversions use internationally defined factors and are exact where the definitions are exact (for example, 1 inch = 2.54 cm). Displayed results are rounded for readability.
People also ask
How many kilometers is 100 nautical miles?
100 nautical miles equals 185.2 kilometers, since you multiply by exactly 1.852.
What is the difference between a nautical mile and a regular mile?
A nautical mile is 1.852 km, while a statute (land) mile is about 1.609 km, so a nautical mile is roughly 15 percent longer. The nautical mile is based on one minute of latitude, whereas the statute mile is an older land-survey unit.
How fast is 1 knot in km/h?
One knot is one nautical mile per hour, which equals 1.852 km/h. So 20 knots is about 37 km/h.
Why is a nautical mile 1.852 km exactly?
It was originally defined as one minute of arc of latitude on Earth's surface. In 1929 the international community fixed it at exactly 1,852 meters for consistency, giving 1 nmi = 1.852 km.
How do you convert kilometers back to nautical miles?
Divide the kilometers by 1.852, or multiply by about 0.5400. For example, 10 km is about 5.4 nautical miles.
How many kilometers is 5 nautical miles?
5 nautical miles equals 9.26 kilometers (5 × 1.852).
Is a nautical mile the same in aviation and at sea?
Yes. Aviation and maritime navigation both use the international nautical mile of exactly 1.852 km, and both measure speed in knots (nautical miles per hour).
What is 200 nautical miles in km?
200 nautical miles is 370.4 kilometers. This is a common figure because it matches the typical outer limit of a country's Exclusive Economic Zone.
Is 20 knots the same as 20 mph?
No, 20 knots is faster. A knot is one nautical mile per hour, and a nautical mile is 1.852 km, so 20 knots = 20 × 1.852 = 37.04 km/h, which is 23.0 mph; 20 mph is only 32.2 km/h, or about 17.4 knots. The gap is about 15 percent, the same ratio as between the nautical and statute mile.
Why do sailors use knots instead of mph?
Because knots are tied to the nautical mile, which is one minute of latitude, so a speed in knots reads directly off a chart's latitude scale: at 12 knots a vessel covers 12 minutes of latitude, or 12 × 1.852 = 22.2 km, in an hour. Distances at sea are plotted in nautical miles for the same reason, so mixing in statute miles would only add a conversion. The word comes from the knotted log line early sailors trailed behind the ship to count speed.
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Sources & references
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