Mach. Mach is a speed measurement based on the speed of sound. Since sound travels at different speeds in different conditions, the calculations here are given for 20°C in dry air at sea level. Mach is typically used in aviation and space exploration. Mach to Kilometers per hour formula Kilometers per hour A more objective comparison is the Mach number, a nondimensional value, although the Mach number is dependent on altitude (i.e. Mach 1 at sea level is 15% faster than Mach 1 at 50,000 ft). Aircraft. Speed. Altitude. Mach Number. SR-71 Blackbird. 2,275 mph. (3,660 km/h) 80,000 ft. Feb 2, 2021 · In our testing, a 2021 Ford Mustang Mach-E all-wheel-drive Extended Range model launched to 60 mph in 5.1 seconds, raced through the quarter-mile in 13.8 seconds at 101 mph, and managed 0.85 g of Yv6Q.