Knots to mph Converter
If you're wondering how much is a knot, you're in the right place  this knots to mph converter can help you in clearing up your doubts. Type the value into the calculator, and in the blink of an eye, you'll get the answer  equivalent in mph, ft/s, m/s, and km/h. As our calculators are flexible tools, you can also convert mph to knot or any other wind speed unit. Keep reading if you want to know how many mph is a knot or how fast it is. Also, you'll find an informative wind speed chart and all the formulas behind the wind speed units conversions.
How many mph is a knot and how fast is it? What is a nautical mile?
One knot is defined as 1 nautical mile per hour and:
 1.15078 miles per hour (approximately)
 1.852 kilometers per hour (exactly)
 1.68781 feet per second (approximately)
 0.51444 meters per second (approximately)
Nautical miles and knots are the units used in meteorology, aviation, and nautical navigation. What's the difference between them? A nautical mile measures the distance and a knot measures the speed.
One nautical mile historically was defined as one minute of latitude (1/60 of a degree of latitude), which is 1.852 kilometers. That's the average value, as the Earth is not a perfect sphere but a geoid.
Conversion formulas. Knots to mph and mph to knots
To convert between speed units, you can use our knots to mph converter or perform the conversion manually using the formulas:
 knots to mph and mph to knots

V(knots) = 0.868976 * V(mph)

V(mph) = 1.150779 * V(knots)
 knots and km/h

V(knots) = 0.539957 * V(km/h)

V(km/h) = 1.852 * V(knots)
 knots and ft/s

V(knots) = 0.592484 * V(ft/s)

V(ft/s) = 1.687810 * V(knots)
 knots and m/s

V(knots) = 1.943844 * V(m/s)

V(m/s) = 0.514444 * V(knots)
If you need conversion between other units (as there are 20 permutations and we present only 8 of them), take the coefficients from this table:
m/s  km/h  mph  knot  ft/s  

1 m/s =  1  3.6  2.236936  1.943844  3.280840 
1 km/h =  0.277778  1  0.621371  0.539957  0.911344 
1 mph =  0.44704  1.609344  1  0.868976  1.466667 
1 knot =  0.514444  1.852  1.150779  1  1.687810 
1 ft/s =  0.3048  1.09728  0.681818  0.592484  1 
Wind speed chart
Knowing how to convert knots to mph may be useful in many situations, such as e.g.:
 Determining the boat speeds and airspeeds (for example, check our true airspeed calculator)
 Expressing tidal streams, river currents, and wind speeds
 Finding the optimal conditions for a windsurfing or kiteboarding (630 knots is a range usually used, depending on the body weight, kite size, and how skilled you are).
With this wind speed chart, you can assess the prevailing conditions and even estimate them in Beaufort scale:
Description  Range  Beaufort number  knots  mph  km/h  ft/s  m/s 

Calm  <1 mph  0  0  0  0  0  0 
Light air  13 mph  1  2.5  2.88  4.63  4.22  1.29 
Light breeze  47 mph  2  5  5.75  9.26  8.44  2.57 
Gentle breeze  812 mph  3  7.5 10 
8.63 11.51 
13.89 18.52 
12.66 16.88 
3.86 5.14 
Moderate breeze  1318 mph  4  12.5 15 
14.38 17.26 
23.15 27.78 
21.10 25.32 
6.43 7.72 
Strong breeze  2531 mph  6  22.5 25 27.5 
25.89 28.77 31.65 
41.67 46.3 50.93 
37.98 42.20 46.42 
11.57 12.86 14.15 
Moderate gale  3238 mph  7  30 32.5 
34.52 37.4 
55.56 60.19 
50.63 54.85 
15.43 16.72 
Fresh gale  3946 mph  8  35 37.5 40 
40.28 43.15 46.03 
64.82 69.45 74.08 
59.07 63.29 67.51 
18.01 19.29 20.58 
Strong gale  4754 mph  9  42.5 45 47.5 
48.91 51.79 54.66 
78.71 83.34 87.97 
71.73 75.95 80.17 
21.86 23.15 24.44 
Whole gale (storm) 
5563 mph  10  50 52.5 55 
57.54 60.42 63.29 
92.6 97.23 101.86 
84.39 88.61 92.83 
25.72 27.01 28.29 
Violent storm  6473 mph  11  57.5 60 62.5 
66.17 69.05 71.92 
106.49 111.12 115.75 
97.05 101.27 105.49 
29.58 30.87 32.15 
Hurricane  >74 mph  12  65 67.5 70 
74.8 77.68 80.55 
120.38 125.01 129.64 
109.7 113.93 118.15 
33.44 34.72 36.01 
How to use knots to mph converter: 40 knots to mph example
If you are wondering how fast is a knot  or for example 40 knots  have a look at this short stepbystep example:

Think about the unit you want to convert. Let's assume we want to change 40 knots into miles per hour.

Type the value into proper box. In our case, we need to enter 40 into the first part of the tool.

That's it! Our knots to mph converter did the job! Now we know that 40 knots are equal to 46.03 mph. That's quite a lot!