Knots to MPH Calculator
Convert speed from knots to mph, km/h and m/s.
Results update as you type.
How it works
Knots are the standard unit of speed in aviation and at sea, and this calculator converts them to everyday and scientific units. You enter a speed in knots, and it returns the equivalent in miles per hour, kilometers per hour, and meters per second. A knot is defined as one nautical mile per hour, and because a nautical mile is exactly 1.852 kilometers, based on the circumference of the Earth, one knot equals 1.852 kilometers per hour, about 1.151 miles per hour, or roughly half a meter per second. Knots are used for ship and boat speeds, aircraft airspeeds, and wind speeds in marine and aviation weather forecasts, because the nautical mile relates neatly to latitude and longitude for navigation. Converting to miles or kilometers per hour makes these speeds intuitive for people used to road speeds, and meters per second is useful in physics and engineering. For quick reference, 10 knots is about 11.5 mph or 18.5 km/h, and a fast boat at 30 knots is roughly 34.5 mph. This is handy for boaters and pilots translating instrument readings, understanding weather reports that give wind in knots, or comparing a vessel's speed to familiar units. The conversions are exact fixed factors. Enter a speed in knots to convert it to miles per hour, kilometers per hour, and meters per second.
1 knot = 1.150779 mph = 1.852 km/h = 0.514444 m/s
A knot is one nautical mile per hour. Since a nautical mile is 1.852 kilometers, one knot equals 1.852 km/h, which is about 1.151 mph and 0.514 m/s. Multiplying a speed in knots by these fixed factors converts it to each unit.
Source:Unit conversion
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Worked example
How to use this calculator
- 1
Enter your values
Enter speed.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Miles per hour updates instantly as you type — no button to press.
Frequently asked questions
How do I convert knots to mph?
Multiply the speed in knots by 1.150779 to get miles per hour. For example, 10 knots is about 11.51 mph. The calculator also converts to kilometers per hour (multiply by 1.852) and meters per second (multiply by 0.514444), covering the most common speed units in one step.
What is a knot?
A knot is a unit of speed equal to one nautical mile per hour. A nautical mile is 1.852 kilometers, based on the Earth's circumference, which makes knots convenient for navigation using latitude and longitude. Knots are the standard speed unit in maritime and aviation contexts worldwide.
Why are knots used in aviation and sailing?
Knots are used because the nautical mile is tied to the geometry of the Earth: one nautical mile is about one minute of latitude. This makes speed and distance calculations straightforward when navigating with charts and coordinates, which is why ships and aircraft, and the weather forecasts they rely on, use knots for speed and wind.
How fast is 30 knots in mph?
Thirty knots is about 34.5 miles per hour, since each knot is roughly 1.15 mph. That is a fast speed for a boat. For wind, 30 knots is a strong gale. The calculator converts any knot value to mph, km/h, and m/s so you can relate marine and aviation speeds to familiar units.
Is the nautical mile the same as a regular mile?
No. A nautical mile is 1.852 kilometers, or about 1.15 statute (regular) miles, so it is longer. Because a knot is one nautical mile per hour, a speed in knots is a larger number of statute miles per hour. This is why converting knots to mph multiplies by about 1.15 rather than leaving the number unchanged.