Enter a speed, choose the units, and see the conversion plus the same value across every unit. It covers km/h used on our roads, the mph shown by foreign cars and US sources, m/s for physics, and knots for boats and aircraft. Everything runs in your browser.
In all units
- Kilometers per hour (km/h)1 km/h
- Miles per hour (mph)0.621371 mph
- Meters per second (m/s)0.277778 m/s
- Feet per second (ft/s)0.911344 ft/s
- Knot (kn)0.539957 kn
How it works
Each unit is defined by its equivalent in metres per second, the base: your value becomes m/s and then the target unit. One km/h is 1000⁄3600 m/s, one mph is 0.44704 m/s, and one knot is 1852⁄3600 m/s — all from exact definitions, so highway and marine speeds stay accurate.
A useful anchor: 3.6 km/h equals exactly 1 m/s, which is why you multiply m/s by 3.6 to get km/h. Knots come from the nautical mile (1,852 m per hour), so a knot is a touch faster than a km/h — 1 knot ≈ 1.852 km/h.
Practical examples
A foreign car showing mph
A rental abroad reads 70 mph on the motorway. That’s about 112.65 km/h — enter 70, from mph, to km/h to match our speed limits.
Running pace as m/s
A treadmill set to 12 km/h is running at about 3.33 m/s. Convert km/h to m/s to compare with a physics figure or a track readout.
Wind speed in knots
A marine forecast of 20 knots is about 37.04 km/h. Convert knots to km/h to picture the wind in familiar units.
Frequently asked questions
How do I convert km/h to mph?
Multiply km/h by about 0.621371, or divide by 1.609344. So 100 km/h is about 62.14 mph. The tool uses exact factors, so the result is precise rather than a rounded rule of thumb.
How do I convert mph to km/h?
Multiply mph by 1.609344. For example 60 mph is about 96.56 km/h. Enter the mph value and read the km/h row — handy for reading foreign speedometers and limits.
What is the relationship between m/s and km/h?
Multiply m/s by 3.6 to get km/h, and divide km/h by 3.6 to get m/s, because there are 3,600 seconds in an hour and 1,000 metres in a kilometre. So 10 m/s is 36 km/h.
What is a knot?
A knot is one nautical mile per hour — 1,852 metres per hour, or about 1.852 km/h. It is standard for boats, ships and aircraft because it ties directly to nautical miles and latitude.
When would I use feet per second?
Feet per second (ft/s) appears in US engineering, ballistics and some sports data. One ft/s is 0.3048 m/s. It’s included so US-sourced figures convert cleanly to metric.
Why show every unit at once?
It saves repeated conversions and lets you cross-check quickly. Enter a value and the list underneath shows it in all units, with your chosen target highlighted.
Does it accept decimals and the Serbian comma?
Yes. Type 12,5 or 12.5 km/h — both are read the same — and pasted values with separators are handled. Results show up to six decimals, trailing zeros trimmed.
Are the values I enter kept private?
Yes. Everything is computed in your browser; nothing is uploaded and analytics never sees the numbers.
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