Miles per hour to Mach
Type a value in miles per hour to see it in Mach straight away, or type in the second box to convert back.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Type the value in the miles per hour box.
- Read the result in Mach as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
Ma = mph × 0.001313687622
Multiply the value in miles per hour by 0.001313687622 to get Mach.
Example
To convert 25 mph to Mach: 25 × 0.001313687622 = 0.0328422 Ma.
Conversion table
| Miles per hour (mph) | Mach (Ma) |
|---|---|
| 1 | 0.00131369 |
| 2 | 0.00262738 |
| 3 | 0.00394106 |
| 5 | 0.00656844 |
| 10 | 0.0131369 |
| 20 | 0.0262738 |
| 25 | 0.0328422 |
| 50 | 0.0656844 |
| 100 | 0.131369 |
| 250 | 0.328422 |
| 500 | 0.656844 |
| 1,000 | 1.31369 |
About the units
- Mile per hour
- Covering one international mile (1609.344 m) in one hour, exactly 0.44704 m/s. It is used on roads in the United States and the United Kingdom.
- Mach
- Mach 1 is the speed of sound in air, taken here at sea level in the ISA standard atmosphere at 15 °C, about 340.294 m/s (1225.06 km/h). The speed of sound drops as air gets colder at altitude.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Some factors are rounded to the values given by the official references.
Questions about this tool
How many Mach are in one mile per hour?
1 mph = 0.00131369 Ma.
How do I convert miles per hour to Mach?
Use Ma = mph × 0.001313687622. For example, 25 mph = 0.0328422 Ma.
How many miles per hour are in one Mach?
1 Ma = 761.216 mph.
How do I convert km/h to m/s in my head?
Divide by 3.6, because an hour is 3600 seconds and a kilometer is 1000 meters. For example 72 km/h is 20 m/s; multiply by 3.6 to go back.
Why do Mach values differ between sources?
The speed of sound depends on air temperature. We use 340.294 m/s at sea level and 15 °C; at 11 km altitude it is about 295 m/s, so Mach 1 is slower there.