Mph To Mach Calculator
Convert miles per hour to Mach number, km/h, m/s, and knots instantly. Understand subsonic, transonic, supersonic, and hypersonic flight speeds.
Speed Conversion
Enter a speed in miles per hour to calculate the Mach number
Enter the speed in miles per hour. Standard sea-level speed of sound is 767.2 mph.
Speed Results
Mach number, km/h, m/s, and knots
Enter a speed in mph above and click Calculate Mach to reveal the Mach number and other speed equivalents.
Mach Number Classifications
Reference standard Mach numbers and their corresponding speeds at sea level (15°C). These classifications define the aerodynamic regimes of flight.
| Mach Number | Speed (mph) | Speed (km/h) | Classification |
|---|---|---|---|
| Mach 0.5 | 383.6 mph | 617.5 km/h | Subsonic |
| Mach 0.8 | 613.8 mph | 987.8 km/h | High Subsonic |
| Mach 1.0 | 767.2 mph | 1,234.7 km/h | Transonic / Speed of Sound |
| Mach 1.5 | 1,150.8 mph | 1,852.0 km/h | Supersonic |
| Mach 2.0 | 1,534.4 mph | 2,469.3 km/h | Supersonic |
| Mach 3.0 | 2,301.6 mph | 3,704.0 km/h | High Supersonic |
| Mach 5.0 | 3,836.0 mph | 6,173.4 km/h | Hypersonic |
Mach Number FAQ
Everything you need to know about the Mach number, the speed of sound, and aviation speed classifications.
The Mach number is a dimensionless quantity representing the ratio of the speed of an object to the speed of sound in the surrounding medium. For example, Mach 1 means the object is traveling exactly at the speed of sound, while Mach 2 means it is traveling twice as fast as sound.
To convert miles per hour (mph) to Mach, you divide the speed in mph by the speed of sound in mph. At sea level and standard conditions (15°C), the speed of sound is approximately 767.2 mph. The formula is: Mach = Speed (mph) ÷ 767.2.
At sea level and standard atmospheric conditions (15°C or 59°F), the speed of sound in dry air is approximately 767.2 miles per hour (1,234.7 km/h or 343 m/s).
Yes, the speed of sound primarily depends on the temperature of the air. As altitude increases, the temperature generally decreases, which causes the speed of sound to decrease. For example, at 35,000 feet (cruising altitude for commercial jets), the speed of sound drops to about 660 mph.
Subsonic refers to speeds below Mach 0.8. Transonic refers to speeds around Mach 0.8 to 1.2, where airflow over the object is a mix of subsonic and supersonic. Supersonic refers to speeds between Mach 1.2 and Mach 5.0. Hypersonic refers to extremely high speeds, typically Mach 5.0 and above.
Mach 1 is exactly the speed of sound. At sea level under standard conditions (15°C), Mach 1 is approximately 767.2 miles per hour.