Unit Converters

Speed Converter

Enter any speed in miles per hour, kilometres per hour, metres per second, knots, or feet per second and see all other units update simultaneously, for travel, aviation, science, and sports.

All units update live as you type No sign-up required Browser-only, works offline

Speed

Type in any field; all other units update instantly

Runs entirely in your browser — no data is sent to a server

Features

  • mph, km/h, m/s, knots, ft/s. All update live
  • Handles decimal values and very high speeds
  • Useful reference: speed of light, sound, and Mach 1 presets
  • Click any result to use it as the new base
  • Browser-based, no account needed

How to use it

  1. Select a speed unit or use the default mph.
  2. Type your speed value.
  3. All other units update instantly.
  4. Click any result field to use it as a new input.

Use cases

  • Converting mph to km/h for international speed limits
  • Checking wind speed in knots vs km/h for sailing
  • Physics calculations requiring m/s
  • Sports performance analysis converting sprint speed

Limitations

  • Browser processing depends on available device memory for very large inputs.
  • Tool-specific limits based on file format or browser support are noted on each tool page.
See also

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Questions & answers

Frequently asked

What is 1 knot in km/h?

1 knot = 1.852 km/h exactly (1 nautical mile per hour).

How fast is Mach 1?

Mach 1 (speed of sound at sea level) ≈ 343 m/s, 1235 km/h, or 767 mph at 20 °C.