Conversion Table
Mach
to kilometers per hour Conversion Table: 
Ma to kph
1.0 = 1225.03
2.0 = 2450.06
3.0 = 3675.09
4.0 = 4900.12
5.0 = 6125.15 
Mach
to kilometers per hour
6.0 = 7350.18
7.0 = 8575.21
8.0 = 9800.24
9.0 = 11025.27
10 = 12250.3 
kilometers per hour
to Mach Conversion Table: 
kph to Ma
1.0 = 0.00082
2.0 = 0.00163
3.0 = 0.00245
4.0 = 0.00327
5.0 = 0.00408

kilometers per hour to Mach
6.0 = 0.0049
7.0 = 0.00571
8.0 = 0.00653
9.0 = 0.00735
10 = 0.00816

Mach number (Ma or M) is the speed of an object moving in air, divided by the speed of sound at that particular conditions, including temperature and pressure. At Standard Sea Level and temperature 15 degrees Celsius, the speed of sound is 1225.03 kilometers per hour, kph (km/h) = 761.2 mph = 340.3 meters per second (m/s) = 1116 foot per second (ft/s) = 661.5 knots (kn, kt or kts). The speed of sound is equal to 1091 kph (km/h) = 678 mph at temperature 48 degrees F and altitude 30000 feet . 