Enter a speed in miles per hour to find its equivalent in knots, or switch directions to convert knots to mph.
Advanced options
Table of contents
How to use our MPH to Knots Converter
- Choose "Miles per hour to knots" if your starting speed is in mph, or choose "Knots to miles per hour" if it is in kn.
- Enter a speed of 0 or more in the active unit. You can type a matching suffix, such as "60 mph" or "10 kn".
- Open "Advanced options" if you need more or fewer digits after the decimal point in the displayed answer.
- Click "Calculate" and use the first result card as the converted speed.
- Sanity-check the answer: a positive mph value becomes a smaller number in knots, while a positive knot value becomes a larger number in mph.
Definitions
Miles per hour (mph): A speed in statute miles traveled per hour.
Knot (kn): A speed of one nautical mile per hour. A knot is already a speed unit. [2]
Nautical mile: A distance of exactly 1,852 meters.
Statute mile: The usual US land mile, equal to exactly 1,609.344 meters.
Decimal places: Digits shown to the right of the decimal point. They affect displayed rounding only.
Common mistakes and quick fixes
Mistake: Choosing the reverse direction because both units measure speed.
Fix: Start with the unit printed beside the speed you have, then choose the direction that begins with that unit.
Mistake: Calling a knot "knots per hour."
Fix: A knot already means one nautical mile per hour. Use "kn" if you add a unit suffix.
Mistake: Entering "10 mph" after choosing "Knots to miles per hour."
Fix: Enter a knot value, such as "10 kn," or change the conversion direction.
Mistake: Using a comma as a decimal mark, such as "1,5."
Fix: Use a decimal point for decimals. Commas are accepted only as thousands separators, such as "1,000.5."
Mistake: Rounding the starting speed before converting it.
Fix: Enter the most precise starting speed available, then set the displayed decimal places after conversion.
Limitations & Key Assumptions / Boundary Conditions
- The converter accepts nonnegative speed values only; negative values are outside this speed-entry task.
- The result changes units only. It does not calculate wind, current, heading, ground speed, airspeed, or instrument error.
- A low decimal setting can display a very small nonzero converted speed as zero. Increase "Result decimal places" to show more detail.
- Confirm the source unit before converting. Weather, boating, and aviation material may use mph or kn for different kinds of speed.
Methodology
Conversion method
A statute mile is exactly 1,609.344 meters, and a nautical mile is exactly 1,852 meters. Because both speeds use one hour, the calculator converts the distance units and keeps the time unit unchanged.
kn = mph × 1609.344 / 1852
mph = kn × 1852 / 1609.344
Worked example
For 60 mph, calculate 60 × 1,609.344 / 1,852 = 52.13857451403887 kn. With three decimal places selected, the displayed answer is 52.139 kn. In reverse, 10 kn converts to 11.507794480235425 mph before rounding.
Display rounding
The calculator uses the unrounded converted value, then rounds only the visible answer to the selected number of decimal places. It assumes the entered number is a speed in the chosen source unit; it does not determine which type of speed the source reported.