Knots to Mach Number Converter
Enter the speed in knots below to convert it to Mach number.
Result in Mach Number:
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How to Convert Knots to Mach Number
To convert a knot measurement to a Mach measurement, multiply the speed by the conversion ratio. One knot is equal to Mach 0.0015, so use this simple formula to convert:
Mach number = knots × 0.0015
The Mach number is equal to the speed in knots multiplied by 0.0015.
For example, here's how to convert 5 knots to Mach number using the formula above.
5 kn = (5 × 0.0015) = Mach 0.007499
Knots and Mach number are both units used to measure speed. Keep reading to learn more about each unit of measure.
What Is a Knot?
One knot is equal to a speed of one nautical mile per hour,[1] 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.
Learn more about knots.
What Is 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.[2]
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 |
Learn more about Mach number.
Knot to Mach Conversion Table
The chart below shows various speeds in knots and the equivalent Mach number.
| Knots | Mach Number |
|---|---|
| 166.68 kn | Mach 0.25 |
| 333.37 kn | Mach 0.5 |
| 500.05 kn | Mach 0.75 |
| 666.74 kn | Mach 1 |
| 1,000 kn | Mach 1.5 |
| 1,333 kn | Mach 2 |
| 1,667 kn | Mach 2.5 |
| 2,000 kn | Mach 3 |
| 2,334 kn | Mach 3.5 |
| 2,667 kn | Mach 4 |
| 3,000 kn | Mach 4.5 |
| 3,334 kn | Mach 5 |
| 3,667 kn | Mach 5.5 |
| 4,000 kn | Mach 6 |
| 4,334 kn | Mach 6.5 |
| 4,667 kn | Mach 7 |
| 5,001 kn | Mach 7.5 |
| 5,334 kn | Mach 8 |
| 5,667 kn | Mach 8.5 |
| 6,001 kn | Mach 9 |
| 6,334 kn | Mach 9.5 |
| 6,667 kn | Mach 10 |
References
- NASA, Knots Versus Miles per Hour, https://www.grc.nasa.gov/WWW/K-12/WindTunnel/Activities/knots_vs_mph.html
- NASA, Mach Number, https://www.grc.nasa.gov/WWW/BGH/mach.html