Converting Between Mach Number and Kilometers per Hour
When analyzing aircraft speeds, there is sometimes a need to convert Mach number to kilometers per hour (KPH). While Mach represents speed as a ratio of the local speed of sound, KPH provides actual velocity in standard metric units. This guide outlines the basic Mach to KPH conversion process.
Reviewing Mach Number
As a refresher, Mach number is calculated as:
Mach Number = Aircraft Velocity / Local Speed of Sound
Since the speed of sound changes with conditions like altitude and temperature, published references provide the speed of sound value to use in conversions:
| Condition | Speed of Sound |
|---|---|
| Sea Level | 1234 KPH |
| 10,000 m altitude | 1112 KPH |
| 20,000 m altitude | 1051 KPH |
So Mach 1 equals 1234 KPH at sea level standard conditions.
Calculating KPH from Mach
To convert from Mach number to KPH, simply multiply the Mach number by the reference speed of sound for the flight conditions.
For example, an aircraft traveling at Mach 0.82 at 20,000 m altitude is traveling at:
0.82 * 1051 KPH = 862 KPH
The process is straightforward since KPH already helps define the reference conditions.
Key Takeaways
The essential concepts for going between Mach and KPH are:
- Mach number defines speed as a ratio of local speed of sound
- Published speed of sound values serve as references
- Use Mach * speed of sound reference = KPH
- Use KPH / speed of sound reference = Mach
- Converted values account for speed of sound differences
So with the appropriate speed of sound reference values, Mach number can easily be converted to absolute metric airspeeds in KPH.
Type a value in the Mach field to convert the value to KPH:
KPH:
Mach to KPH Formula
KPH=Mach*1225.044
Example
.77 mach to kph
943.2838800000001
1.4 mach to kph
1715.0616
2.35 mach to kph
2878.85
8 mach to kph
9800.352
0.70 mach to kph
857.5308
15 mach to kph
18375.66
10 mach to kph
12250.44
0.88 mach to kph
1078.03872
0.87 mach to kph
1065.78828
0.7 mach to kph
857.5308
.9 mach to kph
1102.5396
Mach to KPH Table chart
| Mach | KPH |
| 1 | 1225.044 |
| 2 | 2450.088 |
| 3 | 3675.132 |
| 4 | 4900.176 |
| 5 | 6125.22 |
| 6 | 7350.264 |
| 7 | 8575.308 |
| 8 | 9800.352 |
| 9 | 11025.396 |
| 10 | 12250.44 |
| 11 | 13475.484 |
| 12 | 14700.528 |
| 13 | 15925.572 |
| 14 | 17150.616 |
| 15 | 18375.66 |
| 16 | 19600.704 |
| 17 | 20825.748 |
| 18 | 22050.792 |
| 19 | 23275.836 |
| 20 | 24500.88 |
| 50 | 61252.2 |
| 100 | 122504.4 |
| 500 | 612522 |
Related Converters
1. MPH to KPH
2. MPH to Knots
3. MPH to Mach
4. KPH to MPH
5. KPH to Knots
6. KPH to Mach
7. Knots to MPH
8. Knots to KPH
9. Knots to Mach
10. Mach to MPH
11. Mach to KPH
12. Mach to Knots