Mach Number Conversion

Speedometers are used in vehicles to measure speed

The Mach number is a unit used to measure speed. Use one of the conversion calculators below to convert to another unit of measure, or read on to learn more about Mach.

Mach Conversion Calculators

Choose a unit of speed to convert to.

Mach Definition and Usage

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 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

Background and Origin

The Mach number is named for Austrian physicist Ernst Mach to recognize his work in the study of sound waves.

Mach Number Measurement Conversion Table

Common Mach numbers and the equivalent speed values
Mach number knots speed of sound speed of light miles per hour feet per second kilometers per second kilometers per hour meters per second centimeters per second
Mach 1 666.738661 kn 1 sound 0.0000011441 c 767.269148 mph 1,125 ft/s 0.343 km/s 1,235 km/h 343 m/s 34,300 cm/s
Mach 2 1,333 kn 2 sound 0.0000022882 c 1,535 mph 2,251 ft/s 0.686 km/s 2,470 km/h 686 m/s 68,600 cm/s
Mach 3 2,000 kn 3 sound 0.0000034324 c 2,302 mph 3,376 ft/s 1.029 km/s 3,704 km/h 1,029 m/s 102,900 cm/s
Mach 4 2,667 kn 4 sound 0.0000045765 c 3,069 mph 4,501 ft/s 1.372 km/s 4,939 km/h 1,372 m/s 137,200 cm/s
Mach 5 3,334 kn 5 sound 0.0000057206 c 3,836 mph 5,627 ft/s 1.715 km/s 6,174 km/h 1,715 m/s 171,500 cm/s
Mach 6 4,000 kn 6 sound 0.0000068647 c 4,604 mph 6,752 ft/s 2.058 km/s 7,409 km/h 2,058 m/s 205,800 cm/s
Mach 7 4,667 kn 7 sound 0.0000080089 c 5,371 mph 7,877 ft/s 2.401 km/s 8,644 km/h 2,401 m/s 240,100 cm/s
Mach 8 5,334 kn 8 sound 0.000009153 c 6,138 mph 9,003 ft/s 2.744 km/s 9,878 km/h 2,744 m/s 274,400 cm/s
Mach 9 6,001 kn 9 sound 0.000010297 c 6,905 mph 10,128 ft/s 3.087 km/s 11,113 km/h 3,087 m/s 308,700 cm/s
Mach 10 6,667 kn 10 sound 0.000011441 c 7,673 mph 11,253 ft/s 3.43 km/s 12,348 km/h 3,430 m/s 343,000 cm/s
Mach 11 7,334 kn 11 sound 0.000012585 c 8,440 mph 12,379 ft/s 3.773 km/s 13,583 km/h 3,773 m/s 377,300 cm/s
Mach 12 8,001 kn 12 sound 0.000013729 c 9,207 mph 13,504 ft/s 4.116 km/s 14,818 km/h 4,116 m/s 411,600 cm/s
Mach 13 8,668 kn 13 sound 0.000014874 c 9,974 mph 14,629 ft/s 4.459 km/s 16,052 km/h 4,459 m/s 445,900 cm/s
Mach 14 9,334 kn 14 sound 0.000016018 c 10,742 mph 15,755 ft/s 4.802 km/s 17,287 km/h 4,802 m/s 480,200 cm/s
Mach 15 10,001 kn 15 sound 0.000017162 c 11,509 mph 16,880 ft/s 5.145 km/s 18,522 km/h 5,145 m/s 514,500 cm/s
Mach 16 10,668 kn 16 sound 0.000018306 c 12,276 mph 18,005 ft/s 5.488 km/s 19,757 km/h 5,488 m/s 548,800 cm/s
Mach 17 11,335 kn 17 sound 0.00001945 c 13,044 mph 19,131 ft/s 5.831 km/s 20,992 km/h 5,831 m/s 583,100 cm/s
Mach 18 12,001 kn 18 sound 0.000020594 c 13,811 mph 20,256 ft/s 6.174 km/s 22,226 km/h 6,174 m/s 617,400 cm/s
Mach 19 12,668 kn 19 sound 0.000021738 c 14,578 mph 21,381 ft/s 6.517 km/s 23,461 km/h 6,517 m/s 651,700 cm/s
Mach 20 13,335 kn 20 sound 0.000022882 c 15,345 mph 22,507 ft/s 6.86 km/s 24,696 km/h 6,860 m/s 686,000 cm/s

References

  1. NASA, Mach Number, https://www.grc.nasa.gov/WWW/BGH/mach.html