Speed Converter

Convert between km/h, mph, meters per second, knots, and Mach.

Result

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How to use the Speed Converter

  1. Enter the value you want to convert.
  2. Choose the unit you are converting from.
  3. Choose the unit you are converting to (km/h, mph, m/s, knots or Mach).
  4. The result updates instantly; use swap to reverse the direction.

Conversion factors

1 mph = 1.60934 km/h  |  1 m/s = 3.6 km/h  |  1 knot = 1.852 km/h  |  Mach 1 ≈ 1,234.8 km/h

The converter changes every value to km/h first and then into the target unit, so any pair of units works.

Worked example

Common conversions

100 km/h = 62.14 mph = 27.78 m/s = 54.0 knots

60 mph = 96.56 km/h

Indian expressway limit 120 km/h ≈ 74.6 mph

Where each unit is used

km/h is used on roads in India and most countries; mph in the USA and UK; m/s in physics and wind-speed science; knots in aviation and shipping (one nautical mile per hour); and Mach for aircraft, where Mach 1 is the speed of sound — about 1,235 km/h at sea level and lower at altitude because air is colder.

Tips for accurate results

  • To convert km/h to m/s in your head, divide by 3.6 (90 km/h = 25 m/s).
  • To roughly convert km/h to mph, multiply by 0.62.
  • Mach values here assume sea-level conditions.

Frequently Asked Questions

Divide km/h by 1.609. For example 80 km/h ÷ 1.609 ≈ 49.7 mph.

1 knot is 1 nautical mile per hour, or 1.852 km/h (about 1.15 mph).

The speed of sound depends on air temperature, so Mach 1 is slower at high altitude.

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Content reviewed by Vinod, Easy Smart Calculator · Last updated October 2026