What is a Mach?

Mach is the speed of sound multiplier, used in aviation, missile, and supersonic vehicle specifications.

Overview

Mach is a dimensionless speed ratio comparing an object's speed to the local speed of sound (about 343 m/s in air at sea level, varying with altitude and temperature). Named after Austrian physicist Ernst Mach (1838–1916), who pioneered supersonic photography, the unit became standard with high-speed aviation. Mach 1 = sound speed; Mach 2 = twice sound speed. The Concorde cruised at Mach 2.04, the SR-71 Blackbird reached Mach 3.3, and modern commercial jets cruise at Mach 0.78–0.85 (subsonic). 'Breaking the sound barrier' (first achieved by Chuck Yeager in 1947) means crossing Mach 1 in horizontal flight. Hypersonic missiles operate above Mach 5. Mach is essential in aerodynamics because shock waves, drag, and heating all depend on the relationship between vehicle speed and sound speed. At sea level: Mach 1 ≈ 1,235 km/h ≈ 767 mph ≈ 343 m/s.

Symbol

Convert Mach to all units

Live result

Kilometer per Hour1,225.044 km/h Meter per Second340.29 m/s Mile per Hour761.20705 mph Knot661.47085 kn Foot per Second1,116.437 ft/s Centimeter per Second34,029 cm/s Yard per Minute22,328.74 yd/min Inch per Minute804,468.09 in/min Beaufort Scale340.29 Bft

Relationship to Other Speed Units

1 Ma equals

Visual reference for how the mach relates to other speed units. Each row links to the full converter for that pair.

1 Ma=1,225.044 km/h 1 Ma=340.29 m/s 1 Ma=761.20705 mph 1 Ma=661.47085 kn 1 Ma=1,116.437 ft/s 1 Ma=34,029 cm/s 1 Ma=22,328.74 yd/min 1 Ma=804,468.09 in/min 1 Ma=340.29 Bft

When Is the Mach Used?

Military and supersonic-aircraft speeds
Aerospace engineering
Hypersonic missile specifications

Real-world examples

Concorde: Mach 2.04. F-16 fighter: Mach 2. SR-71 Blackbird: Mach 3.3. Space re-entry: Mach 25+.

Tips for Using the Mach

Mach 1 = ~1225 km/h at sea level, standard conditions.
Local speed of sound decreases with altitude (colder air) — true Mach value varies.
Mach 0.8+ is "transonic"; Mach 1+ supersonic; Mach 5+ hypersonic.

Common Mistakes

Assuming Mach 1 is a fixed speed — depends on altitude and temperature.
Multiplying Mach values as simple ratios across altitudes.
Using Mach for subsonic everyday speeds — not practical.

Convert Mach to Other Speed Units

Mach to Kilometer per Hour

1 Ma = 1,225.044 km/h

Mach to Meter per Second

1 Ma = 340.29 m/s

Mach to Mile per Hour

1 Ma = 761.20705 mph

Mach to Knot

1 Ma = 661.47085 kn

Mach to Foot per Second

1 Ma = 1,116.437 ft/s

Mach to Centimeter per Second

1 Ma = 34,029 cm/s

Mach to Yard per Minute

1 Ma = 22,328.74 yd/min

Mach to Inch per Minute

1 Ma = 804,468.09 in/min

Mach to Beaufort Scale

1 Ma = 340.29 Bft

Convert Other Units to Mach

Kilometer per Hour to Mach

1 km/h = 0.000816 Ma

Meter per Second to Mach

1 m/s = 0.002939 Ma

Mile per Hour to Mach

1 mph = 0.001314 Ma

Knot to Mach

1 kn = 0.001512 Ma

Foot per Second to Mach

1 ft/s = 0.000896 Ma

Centimeter per Second to Mach

1 cm/s = 0.00002939 Ma

Yard per Minute to Mach

1 yd/min = 0.00004479 Ma

Inch per Minute to Mach

1 in/min = 0.000001243 Ma

Beaufort Scale to Mach

1 Bft = 0.002939 Ma

FAQ About the Mach

3 questions

What does the Mach (Ma) measure?

The mach measures speed. Mach is the speed of sound multiplier, used in aviation, missile, and supersonic vehicle specifications.

When is the Mach used?

The mach is used in: Military and supersonic-aircraft speeds; Aerospace engineering; Hypersonic missile specifications. Concorde: Mach 2.04. F-16 fighter: Mach 2. SR-71 Blackbird: Mach 3.3. Space re-entry: Mach 25+.

How accurate are conversions involving the Mach?

All conversions on Units Converter use NIST SP 811 and BIPM reference values, accurate to 8 significant figures.