What this calculator does
Knots to kmh conversion comes up whenever a speed reported in nautical or aviation terms, knots, needs comparing against a road speed or a weather forecast given in kilometres per hour.
A knot is defined as exactly one nautical mile per hour, which converts to exactly 1.852 km/h. Enter a value in either unit, choose the direction, and the other comes out immediately, with the equivalent in miles per hour included as well.
The formula
To convert knots to km/h, multiply by 1.852. To convert km/h to knots, divide by 1.852. This factor is exact, since both the knot and the kilometre trace back to precisely defined distances: the nautical mile (1,852 metres, from one minute of latitude) and the kilometre (1,000 metres).
| Term | Meaning |
|---|---|
| Knot (kn) | A unit of speed equal to one nautical mile per hour, or exactly 1.852 km/h. |
| Nautical mile | Exactly 1,852 metres, historically defined as one minute of latitude, used in marine and air navigation. |
| Km/h | Kilometres per hour, the standard metric unit of speed for road and weather use. |
The inputs explained
| Field | What to enter |
|---|---|
| Value | The value to convert. |
| Convert | Choose whether to convert knots to km/h, or km/h to knots. |
When to use it
Reading a marine or aviation weather forecast
Wind speed and vessel or aircraft speed are usually reported in knots, and converting to km/h makes that figure comparable to a familiar road-speed sense of scale.
Checking 10 knots to km or 20 knots to km
Wind speeds around 10 to 20 knots are common in coastal forecasts; converting them to km/h, about 18.5 and 37 km/h, puts them in more everyday terms.
Comparing a boat's speed rating to a car's
A boat rated for a certain number of knots converts to km/h for a direct comparison against a car's speedometer, since the two are rarely quoted in the same unit.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Knots to km/h, across common wind and vessel speeds
A range of knot values, each converted to km/h.
| Knots | Km/h | Miles per hour |
|---|---|---|
| 5 | 9.260 | 5.75 mph |
| 10 | 18.520 | 11.51 mph |
| 20 | 37.040 | 23.02 mph |
| 30 | 55.560 | 34.52 mph |
| 50 | 92.600 | 57.54 mph |
| 100 | 185.200 | 115.08 mph |
Km/h to knots, across common road and wind speeds
A range of km/h values, each converted to knots.
| Km/h | Knots | Miles per hour |
|---|---|---|
| 10 | 5.400 | 6.21 mph |
| 30 | 16.199 | 18.64 mph |
| 50 | 26.998 | 31.07 mph |
| 80 | 43.197 | 49.71 mph |
| 100 | 53.996 | 62.14 mph |
| 120 | 64.795 | 74.56 mph |
Questions
How do I convert knots to km/h?
Multiply the number of knots by 1.852. For example, 20 knots × 1.852 = 37.04 km/h.
How do I convert km/h to knots?
Divide the number of km/h by 1.852. For example, 100 km/h ÷ 1.852 ≈ 54.0 knots.
What is a knot exactly?
A knot is a speed of one nautical mile per hour. The nautical mile is exactly 1,852 metres, so a knot converts to exactly 1.852 km/h, with no rounding involved in the definition itself.
Why do sailors and pilots use knots instead of km/h or mph?
A knot ties directly to the geography used in navigation: one nautical mile is one minute of latitude, so a speed in knots relates directly to how quickly a vessel or aircraft covers degrees of latitude, which matters for plotting a course.
For the full metric and imperial speed ladder, m/s, km/h, mph and mach, see the speed converter. For length units including the nautical mile on its own, see the length converter.