# Mach Number to Knots Conversion

Enter the Mach number below to convert the speed to knots.

Results in Knots: Mach 1 = 666.738661 kn

## 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:

knots = Mach number × 666.738661

The speed in knots is equal to the Mach number multiplied by 666.738661.

For example, here's how to convert Mach 2 to knots using the formula above.
Mach 2 = (2 × 666.738661) = 1,333.477322 kn

## 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.

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 classifications for various mach numbers.
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, 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 numbers converted to knots
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

1. NASA, Mach Number, https://www.grc.nasa.gov/WWW/BGH/mach.html
2. NASA, Knots Versus Miles per Hour, https://www.grc.nasa.gov/WWW/K-12/WindTunnel/Activities/knots_vs_mph.html