A knot is one nautical mile per hour.
Knots to mph Converter — kn to mph
Convert Knots (kn) to mph (mph) using the exact conversion factor (1 knots = 1.150779448 mph). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Knots to mph 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.
Miles per hour.
Result = input x 0.5144444444 / 0.44704.
Speed uses meters per second as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Knots to mph
Knots and mph both describe speed, and the conversion matters whenever a maritime or aviation speed (knots) needs to be compared against a road speed (mph). Knots is typically associated with used internationally in maritime navigation and aviation, while mph is typically associated with united States (road speed limits and vehicle speedometers).
Formula
mph = knots × 1.15077944802
This factor comes from each unit's defined relationship to the category's base unit: 1 knots equals 0.514444444444 base units, and 1 mph equals 0.44704 base units, so dividing one by the other gives the direct knots-to-mph factor of 1.15077944802.
Simple example
1 kn × 1.150779448 = 1.150779448 mph
1 knots = 1.150779448 mph.
Real-world example
10 kn × 1.150779448 = 11.50779448 mph
10 knots = 11.50779448 mph.
Conversion table
| Knots (kn) | mph (mph) |
|---|---|
| 1 kn | 1.150779448 mph |
| 5 kn | 5.75389724 mph |
| 10 kn | 11.50779448 mph |
| 25 kn | 28.7694862 mph |
| 50 kn | 57.5389724 mph |
| 100 kn | 115.0779448 mph |
Reverse conversion: mph to Knots
1.150779448 mph × 0.8689762419 = 1 kn
1.150779448 mph = 1 knots.
knots = mph × 0.868976241901
For a page dedicated to this direction, see mph to Knots.
Knots vs. mph
| Aspect | Knots | mph |
|---|---|---|
| Family | Non-SI unit accepted for use with SI (maritime/aviation) | US/imperial customary unit |
| Typical use | Ship and boat speed in marine navigation | Road speed limits and vehicle speedometers in the US and UK |
| Where it's used | Used internationally in maritime navigation and aviation | United States (road speed limits and vehicle speedometers) |
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.
Understanding the mph
mph (mph) measures speed. Miles per hour follows directly from the international statute mile (1,609.344 m) divided by one hour. It is classified as a US/imperial customary unit.
Where it's used: United States (road speed limits and vehicle speedometers) United Kingdom (road speed limits)
Uses of the mph today
- Road speed limits and vehicle speedometers in the US and UK
- Weather reporting (wind speed) in the US
- Sports statistics (e.g. pitch speed, wind gusts) in US media
History of the mph
Miles per hour is a compound unit with no separate origin story of its own — it follows automatically once the statute mile was fixed at 5,280 feet in 1593 and later refined to exactly 1,609.344 meters by the 1959 international agreement that also standardized the pound.
Historical origin. mph was not the invention of a single named person; it developed through the process described above.
Knots — sources
- BIPM SI Brochure — Non-SI units accepted for use with SI — Lists the knot among accepted non-SI speed units.
mph — sources
- NIST — International yard and pound (1959) — Basis for the modern mile used in mph.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many mph are in 1 knots?
1 knots equals 1.150779448 mph, using the exact defined conversion factor rather than an estimate.
How do I convert knots to mph?
Multiply the knots value by 1.150779448. The converter above does this instantly to whatever precision you set.
How do I convert mph back to knots?
Use the reverse factor: 1 mph equals 0.8689762419 knots. You can also use the swap control in the converter above to flip the direction instantly.
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).
What is a mph?
mph (mph) measures speed. Miles per hour follows directly from the international statute mile (1,609.344 m) divided by one hour. It is classified as a US/imperial customary unit.
Is the knots to mph 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 knots still used today?
Used internationally in maritime navigation and aviation