Convert Mach to mph using the speed of sound at sea level (Mach 1 ≈ 761 mph), or convert mph to Mach; set altitude or air temperature for more precision.
Mach to mph Formula
The following formulas convert between Mach and speed using the local speed of sound determined by the chosen environment.
v = M × a where a=√(γ R T)
- Standard sea-level (15°C) speed of sound: a ≈ 340.294 m/s ≈ 761.216 mph.
- Constants: γ = 1.4 (dry air), R ≈ 287.05287 J/(kg·K); temperature T in kelvin.
- Unit links: 1 m/s = 2.236936 mph; 1 km/h = 0.621371 mph; 1 kn = 1.150779 mph.
- ISA geopotential-altitude temperature model: −6.5 K/km to 11 km, then 216.65 K to 20 km.
Mach to mph Conversion Table
| Mach | mph |
|---|---|
| 0.1 | 76.122 |
| 0.2 | 152.243 |
| 0.3 | 228.365 |
| 0.4 | 304.486 |
| 0.5 | 380.608 |
| 0.6 | 456.730 |
| 0.7 | 532.851 |
| 0.8 | 608.973 |
| 0.9 | 685.094 |
| 1 | 761.216 |
| 1.2 | 913.459 |
| 1.5 | 1,141.824 |
| 2 | 1,522.432 |
| 2.5 | 1,903.040 |
| 3 | 2,283.648 |
| 4 | 3,044.864 |
| 5 | 3,806.080 |
| * Assumes sea-level ISA at 15°C: Mach 1 ≈ 761.216 mph. | |
How do you convert Mach to mph? Multiply Mach by the local speed of sound in mph: mph = Mach × amph; at sea level (15°C), amph ≈ 761.216, so mph ≈ 761.216 × Mach.
How do you convert mph to Mach? Divide mph by the local speed of sound in mph: Mach = mph ÷ amph; choose Standard, Custom Temperature, or Altitude (ISA) to set amph.
Example Problem
Convert Mach 2.3 at sea level (15°C) to mph.
Use the sea‑level relation: mph = Mach × 761.216.
mph = 2.3 × 761.216 ≈ 1,750.797 mph
