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Type the numeric speed, for example 100 for 100 km/h.
Unit converters
Speed Converter (km/h, mph, knots)
Free online speed converter
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About this tool
About this tool
Speed Converter converts between meters per second, kilometers per hour, miles per hour, knots, feet per second, and centimeters per second using exact relationships such as 1 mph = 0.44704 m/s and 1 knot = 1.852 km/h. Type a value, choose the units, and the result and full comparison table update instantly in your browser.
Convert speeds for driving, running, aviation, and weather reports. The tool covers the units drivers, athletes, pilots, and meteorologists use: kilometers and miles per hour, meters per second, knots, and feet per second. Enter a speed once and read it in every unit instantly.
Built for daily work
- Convert a speed limit sign between mph and km/h when driving abroad.
- Translate wind speeds between knots and km/h for marine forecasts.
- Compare running paces between km/h and m/s for training data.
- Convert aircraft speeds between knots and km/h.
How to use this tool
How to use this tool
Select the units
Choose the source and target units. Swap reverses the direction with one click.
Check the table
The table shows the same speed in all six units for quick comparison.
Key features
Key features
Driving, marine, and air units
km/h and mph for roads, knots for boats and aircraft, m/s and ft/s for physics and weather.
Exact relationships
The converter uses precise definitions, including the exact 0.44704 m/s mile per hour and the 1852 m/h knot.
Instant updates
Results appear with every keystroke; no button presses needed.
Private processing
All conversions happen locally on your device.
Practical use cases
Practical use cases
- Convert a speed limit sign between mph and km/h when driving abroad.
- Translate wind speeds between knots and km/h for marine forecasts.
- Compare running paces between km/h and m/s for training data.
- Convert aircraft speeds between knots and km/h.
- Check physics homework values between m/s and ft/s.
Private by default
For local tools, input is processed in your browser and is not sent to application analytics.
Data processing noticeTechnical details
Technical details
ProcessingLocal browser processing
Supported units6 units across metric, imperial, and navigation systems
InputFree numeric entry
ReferenceExact international definitions
Limitations and important notes
Limitations and important notes
- Mach and other environment-dependent speed measures are not included.
- The tool converts scalar speed, not velocity with direction.
- Extreme magnitudes are shown in scientific notation.
Frequently asked questions
Frequently asked questions
One knot is one nautical mile per hour, exactly 1.852 km/h or about 1.151 mph. It is used in maritime and aviation navigation.
Close but not exact. 60 mph equals 96.56 km/h; 100 km/h equals 62.14 mph.
Mach depends on altitude, temperature, and air pressure, so it is not a fixed unit. This converter sticks to units with exact definitions.
Yes, including decimals and very large or small values. Display may switch to scientific notation for extremes.
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