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Speed Converter

Convert speed values between metric, imperial, maritime, and acoustic units.

About the Speed Converter

Convert speed between metric, imperial, and maritime units — km/h, mph, m/s, knots, and Mach.

How to use the Speed Converter

  1. Enter the speed value.
  2. Select the unit you are converting from and to.
  3. Press Convert to see the result.

Tips for the Speed Converter

  • Unlike the other units here, Mach isn't a fixed conversion factor — the speed of sound changes with air temperature and altitude. This converter uses 343 m/s, the commonly cited reference for dry air at 20°C (68°F) at sea level; Mach 1 is slower at altitude or in colder air.

Example: Speed Converter

Converting 100 km/h to mph

  • Value: 100 km/h
  • Convert to: mph

Result: 62.14 mph

1 km/h ≈ 0.621371 mph, so 100 × 0.621371 ≈ 62.14 mph.

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