--- title: "Speed Converter - km/h, mph, m/s, knots, ft/s, Mach | CanDoYa" description: "Free speed and velocity converter. Enter a value and convert instantly between km/h, mph, m/s, feet per second, knots and Mach - runs in your browser, nothing uploaded." url: https://candoya.com/tools/speed-converter/ locale: en type: browser-tool --- # Speed Converter Category: Converters ## How do you convert between speed units? Pick the unit you have, type a number, and pick the unit you want. This speed converter turns your value into every common unit at once - meters per second, km/h, mph, feet per second, knots and Mach - using exact conversion factors, instantly and entirely in your browser. Most speed units are defined by exact factors, so the conversions are precise rather than approximate: a mile per hour is exactly 0.44704 m/s, a km/h is exactly 0.277778 m/s, a foot per second is 0.3048 m/s and a knot is exactly one nautical mile per hour (0.514444 m/s). Enter a value, choose your *from* and *to* units, and the big number updates as you type, with a reference table showing the same speed in all six units at once. Use the swap arrows to reverse the direction. Nothing is uploaded - the math happens on the page. ## How to use it 1. **Enter a speed** - Type a number in the value field. Decimals are fine - use a dot or a comma, e.g. 100 or 62.5 or 62,5. 2. **Choose the units** - Pick the unit you are converting from next to the number, and the unit you want in the To dropdown. 3. **Read every unit at once** - The big result shows your target unit; the table below shows the same speed in all six units. Use the swap arrows to reverse it, or Copy result to grab the figure. ## Who it's for - **Driving abroad** - reading a speed limit in km/h when you think in mph, or the reverse, so you know how fast 100 km/h or 70 mph really is. - **Weather and wind** converting a forecast wind speed between km/h, mph, m/s and knots. - **Sailing and aviation** working with knots alongside km/h and mph, or checking an aircraft speed against Mach. - **Running and cycling** converting a pace or top speed between m/s, km/h and mph. - **Physics and engineering** checking a velocity conversion with exact factors instead of a rounded rule of thumb. ## Expert note One conversion to keep in your head: 100 km/h is 62.14 mph and 60 mph is 96.56 km/h - close enough that drivers often use 'add half again' as a rough rule (60 x 1.6 is about 96). The unit people misuse most is the knot: a knot is one nautical mile per hour, not one mile per hour, so a 20-knot wind is 23 mph, not 20. Mach is the odd one out here because it is not a fixed speed at all - it is a ratio to the local speed of sound, which drops with temperature and altitude. This tool uses Mach 1 = 340.29 m/s (the ICAO standard-atmosphere value at sea level, 15 deg C); at 11 km cruising altitude the speed of sound is nearer 295 m/s, so real aircraft reach Mach 1 at a lower ground speed than the sea-level figure suggests. ## Frequently asked questions ### Is the speed converter free? Yes - it is 100% free, with no sign-up and no limits. Every conversion runs in your browser and nothing you type is uploaded or stored. ### Which speed units does it convert? Six units: meters per second (m/s), kilometers per hour (km/h), miles per hour (mph), feet per second (ft/s), knots (kn) and Mach. You can convert between any two of them. ### How do I convert km/h to mph? Multiply km/h by 0.621371 to get mph, since 1 mph is 1.609344 km/h. So 100 km/h is about 62.14 mph and 50 km/h is about 31.07 mph. Enter the value and this tool shows it instantly. ### How do I convert mph to km/h? Multiply mph by 1.609344 to get km/h. So 60 mph is 96.56 km/h and 70 mph is 112.65 km/h. A quick mental estimate is to add about 60%. ### What is a knot and how fast is it? A knot is one nautical mile per hour, used at sea and in the air. One knot is 1.852 km/h or about 1.151 mph, so a 20-knot wind is roughly 37 km/h or 23 mph. It is not the same as a mile per hour. ### How fast is Mach 1? Mach is a ratio to the local speed of sound, not a fixed speed. At sea level in standard conditions Mach 1 is about 340.29 m/s (1,225 km/h or 761 mph), but the speed of sound falls with temperature, so Mach 1 is slower at altitude. This tool uses the sea-level value. ### Does it work with decimals and commas? Yes. You can type a dot or a comma as the decimal mark, so both 62.5 and 62,5 are read as the same number. Whitespace is ignored. ## Related tools - [Length Converter](https://candoya.com/tools/length-converter/) - [Temperature Converter](https://candoya.com/tools/temperature-converter/) - [Meters to Feet Converter](https://candoya.com/tools/meters-to-feet/) --- *Markdown edition of , published for AI agents and other automated readers. Index of key pages: .*