Speed Converter
Convert speeds for driving, running, sailing, aviation and physics between kilometres per hour, miles per hour, metres per second, knots, feet per second and Mach.
Runs in your browser
How to use
- Enter a speed.
- Choose the units.
- Read the converted speed.
How it works
Units convert through metres per second: 1 km/h = 1/3.6 m/s, 1 mph = 0.44704 m/s exactly, 1 knot = 1 nautical mile per hour = 0.5144 m/s. Mach 1 is taken as 340.29 m/s, the speed of sound at sea level at 15 °C; in reality it depends on air temperature.
Examples
- Speed limit
- 130 km/h = 80.8 mph.
- Wind
- 25 knots = 46.3 km/h.
Common uses
- Driving abroad
- Running pace and cycling
- Sailing and aviation
Privacy & security
This tool runs entirely in your browser. Your files and text are never uploaded to our servers — processing happens on your device and results are created locally. How each tool handles files
Frequently asked questions
Why do pilots and sailors use knots?
A knot is one nautical mile per hour, and a nautical mile corresponds to one minute of latitude, which simplifies navigation.
Is Mach a fixed speed?
No, it's relative to the local speed of sound, which falls with temperature.
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