Speed Converter
Convert between km/h, mph, m/s, knots and Mach.
Converted locally in your browser — nothing is uploaded.
- All six units update together.
- Includes knots for aviation and marine speeds, and Mach for supersonic figures.
- Runs in your browser.
Why this is private
- Converted locally in your browser — nothing is uploaded.
- Open your browser's DevTools → Network tab while using this tool — you won't see a request carrying your input, because it never leaves your device.
- Nothing you enter is uploaded to a server or shared with us — the processing happens entirely on your device.
Overview
Converts speed between kilometers per hour, miles per hour, meters/feet per second, knots and Mach.
How to use it
- 1Enter a value and pick its unit.
- 2Pick the target unit, or use a popular-conversion shortcut.
- 3The result updates instantly.
Frequently asked questions
What people use it for
Read a speed limit while driving abroadConvert a 100 km/h limit to about 62 mph.
Compare a running or cycling paceSwitch between km/h and m/s for a training figure.
Interpret a wind speedConvert a forecast in knots or m/s to km/h or mph.
Convert an aircraft or missile speedTurn a Mach figure into km/h or mph, or the reverse.
Check a datasheet figureConvert a rated speed to the unit you work in.
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Speed Converter