Speed is measured in units such as km/h, mph, m/s, ft/s, kn. Pick a source and target unit above, enter a value, and the result appears instantly — free and entirely in your browser. Below you'll find the most common individual conversions as dedicated pages.
Which speed units are there?
- Kilometers per hour (km/h) — Kilometres per hour (km/h) is the everyday speed unit for road traffic in most of the world: speedometers, speed limits and weather reports all use it.
- Miles per hour (mph) — Miles per hour (mph) is the road-speed unit in the US and UK. One mph equals exactly 1.609344 km/h — a 70 mph motorway limit is about 113 km/h.
- Meters per second (m/s) — Metres per second (m/s) is the SI unit of speed, used in physics and for wind speeds. One m/s equals exactly 3.6 km/h.
- Feet per second (ft/s) — Feet per second (ft/s) is the imperial counterpart of metres per second, exactly 0.3048 m/s. It appears in US engineering, ballistics and ventilation specifications.
- Knot (kn) — The knot (kn) is one nautical mile per hour — exactly 1.852 km/h. It is the standard speed unit in shipping and aviation, and for wind in marine forecasts.
Key facts about speed
Road speeds are posted in km/h in most countries but in mph in the US and UK; shipping and aviation use knots, physics and wind data use metres per second. Converting between them is routine for travel, sailing and sport.
One knot is exactly 1.852 km/h — one international nautical mile (1,852 m, standardised in 1929) per hour. And 100 km/h equals 62.137 mph or 27.778 m/s.
How to use the speed converter
- Pick the source unit and enter the speed value.
- Pick the target unit — the result appears instantly.
- Use the swap button to reverse the direction.
Everything runs locally in your browser — no uploads, no waiting, no limits, and it even works offline.