Kilometers per hour.
km/h to Knots Converter — km/h to kn
Convert km/h (km/h) to Knots (kn) using the exact conversion factor (1 km/h = 0.5399568035 knots). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
km/h to Knots converter
Converter
Speed Converter
Convert road, aviation, marine, lab, and scientific speed units.
Context values
Some unit families need one extra value for a physically accurate result.
A knot is one nautical mile per hour.
Result = input x 0.2777777778 / 0.5144444444.
Speed uses meters per second as the base unit.
Reserved above the conversion cards and below the converter.
About Converting km/h to Knots
km/h and Knots both describe speed, and the conversion matters whenever a maritime or aviation speed (knots) needs to be compared against a road speed (mph). km/h is typically associated with standard road-speed unit worldwide except the US, while Knots is typically associated with used internationally in maritime navigation and aviation.
Formula
knots = km/h × 0.539956803456
This factor comes from each unit's defined relationship to the category's base unit: 1 km/h equals 0.277777777778 base units, and 1 knots equals 0.514444444444 base units, so dividing one by the other gives the direct km/h-to-knots factor of 0.539956803456.
Simple example
1 km/h × 0.5399568035 = 0.5399568035 kn
1 km/h = 0.5399568035 knots.
Real-world example
10 km/h × 0.5399568035 = 5.399568035 kn
10 km/h = 5.399568035 knots.
Conversion table
| km/h (km/h) | Knots (kn) |
|---|---|
| 1 km/h | 0.5399568035 kn |
| 5 km/h | 2.699784017 kn |
| 10 km/h | 5.399568035 kn |
| 25 km/h | 13.49892009 kn |
| 50 km/h | 26.99784017 kn |
| 100 km/h | 53.99568035 kn |
Reverse conversion: Knots to km/h
0.5399568035 kn × 1.852 = 1 km/h
0.5399568035 knots = 1 km/h.
km/h = knots × 1.852
km/h vs. Knots
| Aspect | km/h | Knots |
|---|---|---|
| Family | SI-derived (metric) unit | Non-SI unit accepted for use with SI (maritime/aviation) |
| Typical use | Road speed limits and vehicle speedometers outside the US | Ship and boat speed in marine navigation |
| Where it's used | Standard road-speed unit worldwide except the US | Used internationally in maritime navigation and aviation |
Understanding the km/h
km/h (km/h) measures speed. Kilometers per hour follows directly from the kilometer divided by one hour. It is classified as a SI-derived (metric) unit.
Where it's used: Standard road-speed unit worldwide except the US
Uses of the km/h today
- Road speed limits and vehicle speedometers outside the US
- Weather reporting (wind speed) in most countries
History of the km/h
Km/h is a compound unit with no independent origin story — it follows automatically once the kilometer and hour were each standardized, becoming the default speed unit as metric countries motorized through the 20th century.
Historical origin. km/h was not the invention of a single named person; it developed through the process described above.
Understanding the Knots
Knots (kn) measures speed. A knot is one nautical mile per hour; since the nautical mile is exactly 1,852 meters, a knot is exactly 1,852/3,600 m/s. It is classified as a Non-SI unit accepted for use with SI (maritime/aviation).
Where it's used: Used internationally in maritime navigation and aviation
Uses of the Knots today
- Ship and boat speed in marine navigation
- Aircraft airspeed and wind speed reporting in aviation
- Marine weather forecasts (wind speed)
History of the Knots
The knot gets its name from an old nautical method of measuring speed: sailors trailed a 'log line' with evenly spaced knots behind a ship and counted how many knots paid out over a fixed time, giving a direct speed reading in 'knots.'
The nautical mile it's based on was itself standardized internationally in 1929 (the International Nautical Mile, 1,852 m exactly), tying the knot to a precise value still used in shipping and aviation today.
Historical origin. Knots was not the invention of a single named person; it developed through the process described above.
km/h — sources
- BIPM SI Brochure — Non-SI units accepted for use with SI — Basis for compound metric units like km/h.
Knots — sources
- BIPM SI Brochure — Non-SI units accepted for use with SI — Lists the knot among accepted non-SI speed units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many knots are in 1 km/h?
1 km/h equals 0.5399568035 knots, using the exact defined conversion factor rather than an estimate.
How do I convert km/h to knots?
Multiply the km/h value by 0.5399568035. The converter above does this instantly to whatever precision you set.
How do I convert knots back to km/h?
Use the reverse factor: 1 knots equals 1.852 km/h. You can also use the swap control in the converter above to flip the direction instantly.
What is a km/h?
km/h (km/h) measures speed. Kilometers per hour follows directly from the kilometer divided by one hour. It is classified as a SI-derived (metric) unit.
What is a knots?
Knots (kn) measures speed. A knot is one nautical mile per hour; since the nautical mile is exactly 1,852 meters, a knot is exactly 1,852/3,600 m/s. It is classified as a Non-SI unit accepted for use with SI (maritime/aviation).
Is the km/h to knots conversion exact?
Yes. A knot is one nautical mile per hour; since the nautical mile is exactly 1,852 meters, a knot is exactly 1,852/3,600 m/s. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the km/h still used today?
Standard road-speed unit worldwide except the US