Mach to knots
Type a value in Mach to see it in knots 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 Mach box.
- Read the result in knots as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
kn = Ma × 661.4785944
Multiply the value in Mach by 661.4785944 to get knots.
Example
To convert 25 Ma to knots: 25 × 661.4785944 = 16,537 kn.
Conversion table
| Mach (Ma) | Knots (kn) |
|---|---|
| 1 | 661.479 |
| 2 | 1,322.96 |
| 3 | 1,984.44 |
| 5 | 3,307.39 |
| 10 | 6,614.79 |
| 20 | 13,229.6 |
| 25 | 16,537 |
| 50 | 33,073.9 |
| 100 | 66,147.9 |
| 250 | 165,370 |
| 500 | 330,739 |
| 1,000 | 661,479 |
About the units
- 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.
- Knot
- One nautical mile (1852 m) per hour, about 0.514444 m/s. It is the speed unit of aviation, shipping and wind reports.
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 knots are in one Mach?
1 Ma = 661.479 kn.
How do I convert Mach to knots?
Use kn = Ma × 661.4785944. For example, 25 Ma = 16,537 kn.
How many Mach are in one knot?
1 kn = 0.00151176 Ma.
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.