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