1 knot = 1.1507794 mph
1 kn = 1.15078 mph · type math like (12*4)+6.5
Knots to mph is used by sailors, pilots and storm watchers. Boats and aircraft report speed in knots and hurricane advisories often include them, while the public thinks in miles per hour.
Aviation uses knots for airspeed and wind. A crosswind of 25 kn, which is 28.8 mph, is near the limit for many light aircraft. Airliners typically take off at 140–160 kn, which is 161–184 mph.
Marine weather forecasts use knots too. A small craft advisory in the US is issued for winds of 22–33 kn, which is 25.3–38 mph. Gale warnings start at 34 kn, or 39.1 mph.
Ships' speeds are always in knots. A container ship cruising at 18 kn is moving at 20.7 mph, while the fastest passenger ferries reach 40 kn, which is 46 mph.
Remember that 1 knot is 1 nautical mile per hour, and a nautical mile (1,852 m) is longer than a statute mile (1,609 m). That is why the mph figure is always about 15% higher.
Wind turbines and sailing apps sometimes show knots too. A sailing breeze of 12 kn is 13.8 mph, a comfortable wind for most dinghies. Above 25 kn, which is 28.8 mph, many small boats reef their sails.
Aircraft speeds on flight tracking websites may be shown in knots or mph. A Boeing 787 cruising at 488 kn ground speed is moving at 561.6 mph, and with a strong tailwind it can exceed 700 mph.
Coast guards and rescue services report search areas and drift speeds in knots. A current of 2 kn moves a drifting object about 2.3 miles every hour, which helps rescuers estimate where to search.
Historic ships were measured in knots too. The Titanic's service speed was about 21 kn, which is 24.2 mph, and the record-breaking SS United States reached 35.6 kn, or 41 mph, in 1952.
Whale watching tours often note that a humpback whale cruises at about 3–9 kn, which is 3.5–10.4 mph.
A quick check: the mph number should be about 15% larger than the knot figure. 40 knots should come out near 46 mph (46.03 exactly). If your result is smaller than the knot figure, you divided by mistake. Remember that knots already include 'per hour', so 40 knots is a speed, while 40 nautical miles is a distance.
mph = kn × 1.150779448
Reverse: 1 mph = 0.86897624 kn.
Convert 30 knots to mph.
Answer: 30 kn = 34.5 mph.
| kn | mph |
|---|---|
| 1 kn | 1.1507794 mph |
| 2 kn | 2.3015589 mph |
| 3 kn | 3.4523383 mph |
| 4 kn | 4.6031178 mph |
| 5 kn | 5.7538972 mph |
| 6 kn | 6.9046767 mph |
| 7 kn | 8.0554561 mph |
| 8 kn | 9.2062356 mph |
| 9 kn | 10.357015 mph |
| 10 kn | 11.507794 mph |
| 11 kn | 12.658574 mph |
| 12 kn | 13.809353 mph |
| 13 kn | 14.960133 mph |
| 14 kn | 16.110912 mph |
| 15 kn | 17.261692 mph |
| kn | mph |
|---|---|
| 16 kn | 18.412471 mph |
| 17 kn | 19.563251 mph |
| 18 kn | 20.71403 mph |
| 19 kn | 21.86481 mph |
| 20 kn | 23.015589 mph |
| 25 kn | 28.769486 mph |
| 30 kn | 34.523383 mph |
| 40 kn | 46.031178 mph |
| 50 kn | 57.538972 mph |
| 75 kn | 86.308459 mph |
| 100 kn | 115.07794 mph |
| 250 kn | 287.69486 mph |
| 500 kn | 575.38972 mph |
| 1 000 kn | 1 150.7794 mph |
A 22 kn cruising speed is 25.3 mph.
A 450 kn ground speed is 517.9 mph.
64 kn sustained wind is 73.6 mph, the hurricane line.
A knot already means per hour.
A knot is 15% faster. 30 kn is 34.5 mph.
Nautical charts use nautical miles, which match one minute of latitude.
One knot is one nautical mile per hour, exactly 1.852 km/h or 1.15078 mph.
Origin. Sailors once measured speed by letting out a rope knotted at regular intervals behind the ship and counting knots in a set time.
Used today. Marine and aviation speeds, and wind in aviation forecasts worldwide.
1 mph = 1.609344 km/h.
Origin. British road speed unit.
Used today. Road speeds and US public weather forecasts.
It equals one minute of latitude, fixed at 1,852 m in 1929.
11.5 mph.
115.1 mph.
Yes, approach speeds are given in knots of indicated airspeed.