Knots to MPH
A knot is one nautical mile per hour, and a nautical mile is exactly 1,852 metres against the statute mile's 1,609.344, so knots to miles per hour is one multiplication: mph = knots × 1.150779448. That makes 10 knots 11.5077944802 mph, 20 knots 23.0155889605 mph and 40 knots 46.0311779209 mph. This page opens the converter on knots and miles per hour ahead of whatever pair you last used, prints the answer to twelve significant digits as you type, and lists the same speed in metres per second, kilometres per hour, miles per hour and feet per second underneath, so a boat, wind or aircraft speed quoted in knots reads in every unit at once. The chart below the converter runs from 1 knot to 600 knots.
1 kn in every speed unit
Knots to mph, km/h and m/s
Every figure is this converter's own output for that speed, rounded for reading: mph and metres per second to two decimals. The kilometres per hour column is exact, because a knot is exactly 1.852 km/h.
| Knots | mph | km/h | m/s |
|---|---|---|---|
| 1 kn | 1.15 | 1.852 | 0.51 |
| 2 kn | 2.30 | 3.704 | 1.03 |
| 3 kn | 3.45 | 5.556 | 1.54 |
| 5 kn | 5.75 | 9.26 | 2.57 |
| 10 kn | 11.51 | 18.52 | 5.14 |
| 15 kn | 17.26 | 27.78 | 7.72 |
| 20 kn | 23.02 | 37.04 | 10.29 |
| 25 kn | 28.77 | 46.3 | 12.86 |
| 30 kn | 34.52 | 55.56 | 15.43 |
| 35 kn | 40.28 | 64.82 | 18.01 |
| 40 kn | 46.03 | 74.08 | 20.58 |
| 45 kn | 51.79 | 83.34 | 23.15 |
| 50 kn | 57.54 | 92.6 | 25.72 |
| 60 kn | 69.05 | 111.12 | 30.87 |
| 70 kn | 80.55 | 129.64 | 36.01 |
| 80 kn | 92.06 | 148.16 | 41.16 |
| 100 kn | 115.08 | 185.2 | 51.44 |
| 120 kn | 138.09 | 222.24 | 61.73 |
| 150 kn | 172.62 | 277.8 | 77.17 |
| 200 kn | 230.16 | 370.4 | 102.89 |
| 250 kn | 287.69 | 463 | 128.61 |
| 300 kn | 345.23 | 555.6 | 154.33 |
| 400 kn | 460.31 | 740.8 | 205.78 |
| 500 kn | 575.39 | 926 | 257.22 |
| 600 kn | 690.47 | 1,111.2 | 308.67 |
Common questions
- How many mph is 1 knot?
- 1.15077944802 mph. Multiply knots by 1.150779448 to get miles per hour: 10 knots is 11.5077944802 mph, 20 knots is 23.0155889605 mph, 30 knots is 34.5233834407 mph and 50 knots is 57.5389724012 mph. Going the other way, multiply mph by 0.868976241901, so 60 mph is 52.138574514 knots.
- What is the formula for knots to mph?
- mph = knots × 1852 / 1609.344. A knot is one nautical mile per hour and the international nautical mile is exactly 1,852 metres, while the statute mile behind mph is exactly 1,609.344 metres, so the ratio is the exact fraction 57875/50292, or about 1.1507794480235 as a decimal. This converter carries the speed through metres per second using those defined figures rather than a rounded 1.15, which is why 10 knots comes back as 11.5077944802 rather than 11.5.
- How do I convert knots to mph in my head?
- Add 15 percent. Twenty knots is 20 plus 3, so about 23 mph against the exact 23.0155889605, and 40 knots is 40 plus 6, so about 46 mph against 46.0311779209. The shortcut runs low by 0.07 percent, which is roughly a tenth of a mile per hour even at 150 knots. Use it for a quick read of a forecast and use the converter when the digits matter.
- Why is a knot not the same as a mile per hour?
- Because the two miles are different lengths. The nautical mile of 1,852 metres is close to one minute of latitude, so a degree of latitude is about 60 nautical miles anywhere on the globe, which is what keeps knots in use at sea, in the air and in wind forecasts. The statute mile behind mph is 1,609.344 metres, about 13 percent shorter. The same speed therefore reads about 15 percent higher in mph than it does in knots.
- Is a knot exactly 1.852 km/h?
- Yes, exactly. The nautical mile is defined as 1,852 metres and an hour is 3,600 seconds, so one knot is exactly 1.852 km/h, or approximately 0.514444444444 m/s, and the kilometres per hour column of the chart below is exact rather than rounded. Miles per hour is not so tidy: 1852 divided by 1609.344 is 57875/50292, and 50292 has 11 and 127 among its factors, so that decimal never terminates. The page rounds it at twelve significant digits.
- Can I convert mph back to knots on this page?
- Yes. The swap button between the two boxes reverses the pair, so the page becomes mph to knots: 100 mph is 86.8976241901 knots and 65 mph is 56.4834557235 knots. Both unit menus stay open as well, so the same number will go from knots to kilometres per hour, metres per second or feet per second without leaving the page, and Copy result copies the figure exactly as printed, without the thousands separators.
- Why does the page open on knots and mph when I last converted something else?
- Because a page that names a pair should show that pair. This one sets knots and miles per hour on arrival, ahead of whatever the converter last remembered, and it leaves the main unit converter's own memory alone: go back there and it is still on the pair you left it on. The number you last typed does travel with you, since it is usually the one you are still working on.
- Is anything I type sent anywhere?
- No. The conversion is arithmetic against a table of factors that ships with the page, so it runs in your browser with nothing uploaded and no account, and it keeps working with no network connection once the page has loaded.
Conversion factors are the exact legal definitions where one exists. An inch is exactly 2.54 cm and a pound exactly 0.45359237 kg, so those conversions are exact rather than approximate. Temperature uses offsets rather than factors, and that is shown in the working.