Conversion Table
kilometer per hour
to Mach Conversion Table: 
kph to Mach
1.0 = 0.00082
2.0 = 0.00163
3.0 = 0.00245
4.0 = 0.00327
5.0 = 0.00408

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

Mach
to kilometers per hour Conversion Table: 
Mach 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

1 kilometer per hour (kph) = 0.277777778 meters per second (m/s) = 0.621371192 miles per hour (mph) = 0.911344415 foot / second (ft/s) = 0.539956803 knots (kn, kt or kts). 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 (kph) = 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 = 678 mph at temperature 48 degrees F and altitude 30000 feet. 