Convert Mach to knots or knots to Mach at sea level or at altitude using the standard-atmosphere speed of sound, with km/h, mph and m/s as well.

Mach depends on air temperature: Mach 1 is about 661 kn at 15ยฐC sea level and about 573 kn above 36,000 ft.

Optional settings

Related Calculators

Mach to Kts Formula

The following formula converts a Mach number M to knots at temperature T (Kelvin) using the ideal-gas speed of sound.

kt = M ร— โˆš(ฮณ R T) / (1852 / 3600)
  • ฮณ (dry air) = 1.4
  • R (dry air) โ‰ˆ 287.05287 J/(kgยทK)
  • 1 kt = 1852/3600 m/s exactly (approximately 0.5144444444 m/s)
  • ISA sea level: T = 288.15 K โ†’ a โ‰ˆ 340.294 m/s โ‰ˆ 661.479 kt

Mach to Kts Conversion Table

Mach to Knots (ISA Sea Level, 15ยฐC)
Mach Knots (kt)
0.166.148
0.2132.296
0.3198.444
0.4264.591
0.5330.739
0.6396.887
0.7463.035
0.8529.183
0.9595.331
1.0661.479
1.1727.626
1.2793.774
1.3859.922
1.4926.070
1.5992.218
1.61058.366
1.71124.514
1.81190.661
1.91256.809
2.01322.957
* Values assume ISA sea level (T = 288.15 K), where a โ‰ˆ 661.479 kt.

How do you convert Mach to knots? Choose a temperature model (e.g., ISA sea level), compute the speed of sound a = โˆš(ฮณRT), then kt = Mach ร— a (m/s) รท (1852/3600).

How do you convert knots to Mach? Convert knots to m/s (ร—1852/3600), then Mach = [speed (m/s)] รท a where a = โˆš(ฮณRT) at the chosen temperature.

Example Problem

Convert Mach 0.85 to knots at ISA sea level.

Use a โ‰ˆ 661.479 kt at T = 288.15 K, then kt = 0.85 ร— 661.479.

kt โ‰ˆ 562.257 kt