This calculator allows you to convert from Mile/second to Mach (20°C, 1 atm) and in a reverse direction. To convert from Mile/second to Mach (20°C, 1 atm), enter the amount of Mile/second into the first input and to convert from Mach (20°C, 1 atm) to Mile/second, enter the amount of Mach (20°C, 1 atm) into the second input.