Mach Number to Knots Conversion
Enter the Mach number below to convert the speed to knots.
How to Convert Mach Number to Knots

To convert a Mach measurement to a knot measurement, multiply the Mach number by the conversion ratio. Mach 1 is equal to 666.738661 knots, so use this simple formula to convert:
The speed in knots is equal to the Mach number multiplied by 666.738661.
Mach number and knots are both units used to measure speed. Keep reading to learn more about each unit of measure.
Mach Number
Mach, sometimes also referred to as a Mach number, is the ratio of the speed of an object to the speed of sound.[1]
Mach can be abbreviated as M, and is also sometimes abbreviated as Ma. For example, Mach 1 can be written as 1 M or 1 Ma.
Although Mach can be abbreviated M or Ma, the Mach number is typically expressed with the number after the unit name. For example, the expression Mach 3 is preferred rather than 3 Machs or 3 M.
The speed is classified as either subsonic, transonic, supersonic, or hypersonic depending on the Mach number.
Speed Classification | Mach Number |
---|---|
Subsonic | Mach < 1.0 |
Transonic | Mach = 1.0 |
Supersonic | Mach > 1.0 |
Hypersonic | Mach > 5.0 |
Knots
One knot is equal to a speed of one nautical mile per hour,[2] or one minute of latitude per hour.
Knots can be abbreviated as kn, and are also sometimes abbreviated as kt. For example, 1 knot can be written as 1 kn or 1 kt.
Mach to Knot Conversion Table
Mach Number | Knots |
---|---|
Mach 0.25 | 166.68 kn |
Mach 0.5 | 333.37 kn |
Mach 0.75 | 500.05 kn |
Mach 1 | 666.74 kn |
Mach 1.5 | 1,000 kn |
Mach 2 | 1,333 kn |
Mach 2.5 | 1,667 kn |
Mach 3 | 2,000 kn |
Mach 3.5 | 2,334 kn |
Mach 4 | 2,667 kn |
Mach 4.5 | 3,000 kn |
Mach 5 | 3,334 kn |
Mach 5.5 | 3,667 kn |
Mach 6 | 4,000 kn |
Mach 6.5 | 4,334 kn |
Mach 7 | 4,667 kn |
Mach 7.5 | 5,001 kn |
Mach 8 | 5,334 kn |
Mach 8.5 | 5,667 kn |
Mach 9 | 6,001 kn |
Mach 9.5 | 6,334 kn |
Mach 10 | 6,667 kn |
References
- NASA, Mach Number, https://www.grc.nasa.gov/WWW/BGH/mach.html
- NASA, Knots Versus Miles per Hour, https://www.grc.nasa.gov/WWW/K-12/WindTunnel/Activities/knots_vs_mph.html