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Mach Number Calculator
Convert any speed to Mach number at sea level or any altitude. Includes temperature-corrected speed of sound, shock cone angle, and flight regime classification.
Speed & Conditions
Speed of Sound:
340 m/s
Result
Mach Number
1.000
M
Transonic
Speed (m/s)
340
Speed (km/h)
1224
Speed (mph)
760
Cone Half-Angle
90°
Formula
M = v / c c = 331.4 + 0.6T(°C)
M = 340 / 340 = 1.000
Mach Regime Reference
| Regime | Mach Range | Speed at 15°C | Examples |
|---|---|---|---|
| Subsonic | M < 0.8 | < 272 m/s (978 km/h) | Commercial aircraft cruise (M 0.85 is high subsonic) |
| Transonic | 0.8 – 1.2 | 272–408 m/s | Sound barrier region, shock waves form |
| Supersonic | 1.2 – 5.0 | 408–1700 m/s | Concorde (M 2.04), SR-71 Blackbird (M 3.3) |
| Hypersonic | 5.0 – 10.0 | 1700–3400 m/s | Space Shuttle reentry (M 25), X-43 (M 9.6) |
| High hypersonic | > 10.0 | > 3400 m/s | ICBM reentry, orbital velocity (M ~25) |
Frequently Asked Questions
What is Mach 1 in km/h and mph?
Mach 1 equals the local speed of sound, which depends on temperature. At sea level and 15°C (ISA standard): Mach 1 = 340.3 m/s = 1225 km/h = 761 mph. At 10,000 m altitude (−50°C): Mach 1 = 299.5 m/s = 1079 km/h = 670 mph. Aircraft cross the "sound barrier" at a lower absolute speed at altitude.
How do you calculate Mach number?
Mach = v / c, where v is the object's speed and c is the local speed of sound. For air: c = 331.4 + 0.6 × T(°C). Example: an aircraft at 500 m/s in 20°C air → c = 343.4 m/s → Mach = 500/343.4 = 1.457.
What is the Mach cone angle?
The half-angle (μ) of the Mach cone is sin(μ) = 1/M. At Mach 2: μ = arcsin(0.5) = 30°. At Mach 3: μ = arcsin(0.333) = 19.5°. Higher Mach numbers produce a narrower, more pointed shock cone. At exactly Mach 1, the angle is 90° (a flat Mach disk).