Knots to MPH Converter
Convert knots (nautical miles per hour) to miles per hour instantly
1 knot = 1.150779 mph (exactly 1.852 km/h). To convert knots to mph, multiply by 1.150779, so 20 knots is 23.02 mph.
Knots to Miles per hour converter
Live- 1.6878099 ft/s
- 1.852 km/h
- 0.51444444 m/s
- 0.0015117824 Mach
How to convert knots to mph
A knot is one nautical mile per hour, and a nautical mile is exactly 1,852 meters, a length set by international agreement in 1929 and adopted by the United States in 1954. The ordinary statute mile is 1,609.344 meters. Divide one by the other and you get the conversion factor: 1,852 ÷ 1,609.344 = 1.150779448, so a knot is about 15% faster than a mile per hour. The speed converter sets knots beside km/h, meters per second and Mach when you need a third unit.
The nautical mile is not arbitrary. It was originally one minute of arc of latitude, so 60 nautical miles is roughly one degree along a meridian. That is why sailors and pilots keep using knots: a speed in knots maps directly onto chart distances. The factor has no short decimal form, so the converter carries it to full precision. For metric speeds, 1 knot is exactly 1.852 km/h, which you can take further with the mph to km/h converter.
Step by step
- Take the speed in knots.
- Multiply it by 1.150779 (or by 1.852, then divide by 1.609344).
- Round the result; one decimal place is typical for wind and boat speeds.
See it on a scale
Worked examples
A 10-knot sailing breeze, a 25-knot ferry and the 64-knot threshold where a tropical cyclone becomes a hurricane.
10 kn ÷ 0.8689762419 = 11.507794 mph
= 11.507794 mph
25 kn ÷ 0.8689762419 = 28.769486 mph
= 28.769486 mph
64 kn ÷ 0.8689762419 = 73.649885 mph
= 73.649885 mph
How many knots is 1 mph?
1 mph is 0.868976 knots, so to turn a speed in mph back into knots, divide by 1.150779 or multiply by 0.868976.
The factor is simply the statute mile divided by the nautical mile: 1,609.344 m ÷ 1,852 m. It is useful when a US weather app gives the wind in mph but your boat's instruments, charts and logbook all work in knots. The 39 mph and 74 mph rows below are the rounded thresholds the National Hurricane Center uses in public advisories for tropical storms and hurricanes.
| Miles per hour | Knots |
|---|---|
| 10 mph | 8.69 kn |
| 25 mph | 21.72 kn |
| 39 mph | 33.89 kn |
| 74 mph | 64.3 kn |
| 100 mph | 86.9 kn |
| 500 mph | 434.49 kn |
For kilometers per hour, 1 km/h is 0.539957 knots, so a 20 km/h wind is 10.8 knots. The nautical mile, statute mile and kilometer themselves are on the length converter.
How do I convert knots to mph in Excel or Google Sheets?
Use =A2*1852/1609.344 with knots in cell A2, or Excel's =CONVERT(A2,"kn","mph"); both return 23.0156 for 20 knots.
Writing the factor as 1852/1609.344 keeps the result exact, because both lengths are defined values. Multiplying by 1.15 instead is 0.07% low, harmless for a wind reading but noticeable across a long passage log. Google Sheets accepts the plain multiplication formula unchanged; fill it down a column of logged wind or boat speeds to convert them all at once.
- mph to knots: =A2*1609.344/1852, or =CONVERT(A2,"mph","kn") in Excel.
- Knots to km/h: =A2*1.852.
- Rounded for a report: =ROUND(A2*1852/1609.344,1).
Excel's unit list also includes "admkn", the old British Admiralty knot of 6,080 feet per hour, which is 1,853.184 meters per hour and slightly faster than the international knot. Use "kn" unless a historical document clearly says otherwise.
Knots to mph conversion chart
Knots converted to miles per hour and rounded to two decimal places, from light breezes up to airliner cruising speeds. For a precise figure, type your value into the converter.
| Knots (kn) | Miles per hour (mph) |
|---|---|
| 1 kn | 1.15 mph |
| 2 kn | 2.3 mph |
| 3 kn | 3.45 mph |
| 4 kn | 4.6 mph |
| 5 kn | 5.75 mph |
| 6 kn | 6.9 mph |
| 7 kn | 8.06 mph |
| 8 kn | 9.21 mph |
| 9 kn | 10.36 mph |
| 10 kn | 11.51 mph |
| 12 kn | 13.81 mph |
| 15 kn | 17.26 mph |
| 18 kn | 20.71 mph |
| 20 kn | 23.02 mph |
| 25 kn | 28.77 mph |
| 30 kn | 34.52 mph |
| 35 kn | 40.28 mph |
| 40 kn | 46.03 mph |
| 45 kn | 51.79 mph |
| 50 kn | 57.54 mph |
| 60 kn | 69.05 mph |
| 64 kn | 73.65 mph |
| 80 kn | 92.06 mph |
| 100 kn | 115.08 mph |
| 120 kn | 138.09 mph |
| 150 kn | 172.62 mph |
| 200 kn | 230.16 mph |
| 250 kn | 287.69 mph |
| 300 kn | 345.23 mph |
| 400 kn | 460.31 mph |
| 500 kn | 575.39 mph |
Knots vs mph: what is the difference?
A knot and a mile per hour are both distance-per-hour units, but they count different miles. The nautical mile behind the knot is tied to the shape of the Earth, while the statute mile behind mph comes from land measurement.
| Attribute | Knots | Miles per hour |
|---|---|---|
| Symbol | kn | mph |
| System | Nautical / aviation | Imperial / US |
| Defined as | 1 nmi/h (0.514444 m/s) | 0.44704 m/s |
| One unit equals | 1.1507794 mph | 0.86897624 kn |
| Mile it counts | Nautical mile: exactly 1,852 m | Statute (international) mile: exactly 1,609.344 m |
| Link to the Earth | About one minute of arc of latitude | None; 5,280 feet by definition |
| Set by | International Extraordinary Hydrographic Conference, Monaco, 1929 | 1959 International Yard and Pound Agreement |
| Main users | Ships, aircraft, and marine and aviation weather worldwide | US and UK road traffic, and US public weather forecasts |
4 key differences
- One knot is 1.150779 mph, so the same speed is a number about 13% smaller in knots than in mph.
- The nautical mile is 242.656 m longer than the statute mile.
- The US National Weather Service gives marine and aviation winds in knots but public forecast winds in mph.
- ICAO Annex 5 still permits the knot and the nautical mile alongside SI units in international aviation.
What is a knot?
A knot is a unit of speed equal to one nautical mile per hour: exactly 1,852 meters, or about 1.150779 statute miles, covered in one hour.
The name comes from the chip log, an early speed-measuring device. Sailors threw a wooden board attached to a line over the stern, and the line had knots tied at regular intervals. They counted how many knots ran out while a small sandglass emptied, and that count was the ship's speed. The intervals were chosen so that the count matched nautical miles per hour.
Because a knot already means “nautical miles per hour”, the phrase “knots per hour” is wrong; it would describe acceleration. Say “the boat is doing 12 knots”. Knots are the standard unit for ship speed, aircraft airspeed and, in the US, the wind speeds in aviation weather reports and marine forecasts.
Nautical, statute and kilometer
- 1 nautical mile = 1,852 m = 1.150779 statute miles
- 1 statute mile = 1,609.344 m = 0.868976 nautical miles
- 1 knot = 1.852 km/h = 1.150779 mph
Beaufort wind scale in knots and mph
The Beaufort scale is defined in knots. The mph ranges below are converted from the knot limits, so they differ slightly from the rounded mph values some charts print.
| Force | Description | Knots | mph |
|---|---|---|---|
| 0 | Calm | < 1 | < 1.2 |
| 1 | Light air | 1–3 | 1.2–3.5 |
| 2 | Light breeze | 4–6 | 4.6–6.9 |
| 3 | Gentle breeze | 7–10 | 8.1–11.5 |
| 4 | Moderate breeze | 11–16 | 12.7–18.4 |
| 5 | Fresh breeze | 17–21 | 19.6–24.2 |
| 6 | Strong breeze | 22–27 | 25.3–31.1 |
| 7 | Near gale | 28–33 | 32.2–38 |
| 8 | Gale | 34–40 | 39.1–46 |
| 9 | Strong gale | 41–47 | 47.2–54.1 |
| 10 | Storm | 48–55 | 55.2–63.3 |
| 11 | Violent storm | 56–63 | 64.4–72.5 |
| 12 | Hurricane force | 64+ | 73.6+ |
Hurricane categories: knots to mph
The US National Hurricane Center sets the Saffir-Simpson categories in knots of maximum sustained wind. Its public advisories quote rounded mph, such as 74 mph for Category 1; these are the direct conversions.
| Category | Sustained wind (knots) | Converted (mph) |
|---|---|---|
| Tropical storm | 34–63 kn | 39.1–72.5 mph |
| Category 1 hurricane | 64–82 kn | 73.6–94.4 mph |
| Category 2 hurricane | 83–95 kn | 95.5–109.3 mph |
| Category 3 hurricane | 96–112 kn | 110.5–128.9 mph |
| Category 4 hurricane | 113–136 kn | 130–156.5 mph |
| Category 5 hurricane | 137+ kn | 157.7+ mph |
Typical boat and aircraft speeds
Approximate cruising speeds, which vary with design, load and conditions. Ship and aircraft figures are usually given in knots in official documents.
| Vessel or aircraft | Knots | mph |
|---|---|---|
| Kayak, relaxed paddling | 3–4 kn | 3–5 mph |
| Cruising sailboat | 5–8 kn | 6–9 mph |
| Large container ship | 16–24 kn | 18–28 mph |
| Fast passenger ferry | 30–40 kn | 35–46 mph |
| Cessna 172 cruise (true airspeed) | 110–125 kn | 127–144 mph |
| Jet airliner cruise (true airspeed) | 450–500 kn | 518–575 mph |
Mistakes to avoid with knots
- Using statute miles on a chart. Distances on nautical charts are in nautical miles. If you convert your speed to mph, convert the chart distance to statute miles too, or keep everything in knots.
- Comparing indicated and ground speed. A pilot's airspeed indicator shows indicated airspeed in knots, which is lower than the true airspeed at altitude, and ground speed adds or subtracts the wind. Converting any of these to mph does not change which one it is.
- Rounding the factor to 1.15. It is only about 0.07% off, fine for a quick estimate, but use the exact factor for navigation and logbooks.
- Mixing up m/s wind reports. Some European forecasts give wind in meters per second. One knot is about 0.514 m/s, so a 10 m/s wind is roughly 19.4 knots.
For distances rather than speeds, the km to miles converter helps when a route is given in kilometers, and the km/h to mph converter covers road speeds.
Sources and further reading
The standards and references behind the numbers on this page. Links open in a new tab.
Standards and official sources
Further reading
- KnotWikipedia
- Mile per hourWikipedia
Knots to mph FAQs
Short, exact answers to what people ask most.
How many mph is 1 knot?
One knot is 1.150779 mph. It equals one nautical mile (1,852 m) per hour, which is exactly 1.852 km/h.
What is 20 knots in mph?
20 knots is 23.02 mph. That falls in force 5 (fresh breeze) on the Beaufort scale, and it is a brisk speed for a small motorboat.
Why is a knot faster than a mile per hour?
A knot uses the nautical mile of 1,852 m, while mph uses the statute mile of 1,609.344 m. The nautical mile is about 15% longer, so a knot is about 15% faster.
Is it correct to say knots per hour?
No. A knot already means one nautical mile per hour, so knots per hour would be a rate of acceleration. Just say a boat is doing 15 knots.
What wind speed in knots is a hurricane?
A tropical cyclone becomes a Category 1 hurricane at 64 knots of sustained wind, which is 73.6 mph. The National Hurricane Center rounds this to 74 mph.
How do I convert knots to mph quickly?
Multiply by 1.15, or add 15%. For example, 30 knots is about 34.5 mph; the exact answer is 34.52 mph.
What is 10 knots in mph?
10 knots is 11.5078 mph. On the Beaufort scale that is force 3, a gentle breeze, and a relaxed pace for a cruising sailboat.
What is 50 knots in mph?
50 knots is 57.539 mph, which falls in force 10 (storm) on the Beaufort scale.
How fast is 100 knots in mph?
100 knots is 115.0779 mph, a little under the 110 to 125 knot cruise of a Cessna 172.
What is 500 knots in mph?
500 knots is 575.3897 mph, at the top of the typical true-airspeed cruise range of a jet airliner.
Related conversions
Nautical mile of 1,852 m from the 1929 International Extraordinary Hydrographic Conference and NIST SP 811; mile from the 1959 International Yard and Pound Agreement; wind thresholds from the Beaufort scale and the NOAA National Hurricane Center's Saffir-Simpson scale; aviation units per ICAO Annex 5; spreadsheet syntax from Microsoft Excel's CONVERT documentation. Last updated . How we verify our numbers.