Speed Converter
km/h, mph, m/s, knots and ft/s for driving abroad, running, sailing and flying
km/h, mph, m/s, knots and ft/s for driving abroad, running, sailing and flying. No data leaves your browser – every conversion happens locally.
How the speed units relate
Everything converts through metres per second. One km/h is 1/3.6 m/s, one mph is exactly 0.44704 m/s and one knot is one nautical mile (1,852 m) per hour, about 0.514 m/s.
Runners usually think in pace (minutes per kilometre) rather than speed. Pace is the inverse, so it isn't in the list: divide 60 by your km/h to get minutes per km. 10 km/h works out to 6:00 per km.
Common speed conversions
| 60 mph | 96.6 km/h |
| 100 km/h | 62.1 mph |
| 1 m/s | 3.6 km/h |
| 1 knot | 1.852 km/h |
| 30 mph | 48.3 km/h |
| 120 km/h | 74.6 mph |
Worked examples
An easy run
10 km/h is 2.78 m/s or 6.21 mph, which is the speed most treadmills in the US show as about 6.2.
Sailing wind
A 15-knot breeze is 27.8 km/h or 17.3 mph. Weather apps in Europe tend to show km/h, marine forecasts show knots.
Driving abroad
An 80 km/h limit is 49.7 mph. In the UK the signs are in mph, everywhere else in Europe in km/h.
Speed limits in km/h, mph, m/s and knots
These are the limits you'll see on road signs across Europe, India and Australia, converted for drivers used to mph. Divide km/h by 3.6 for m/s, and by 1.852 for knots.
| km/h | mph | m/s | Knots |
|---|---|---|---|
| 30 km/h | 18.6 mph | 8.33 m/s | 16.2 kn |
| 50 km/h | 31.1 mph | 13.89 m/s | 27.0 kn |
| 60 km/h | 37.3 mph | 16.67 m/s | 32.4 kn |
| 80 km/h | 49.7 mph | 22.22 m/s | 43.2 kn |
| 100 km/h | 62.1 mph | 27.78 m/s | 54.0 kn |
| 120 km/h | 74.6 mph | 33.33 m/s | 64.8 kn |
| 130 km/h | 80.8 mph | 36.11 m/s | 70.2 kn |
Knots per hour and wind in m/s
A knot already means one nautical mile per hour, so "knots per hour" is wrong. It would describe acceleration, not speed. Pilots and sailors just say knots.
Wind speed is the other surprise. Many European forecasts, including the Norwegian service yr.no, give wind in metres per second. A 10 m/s wind sounds mild until you convert it: that's 36 km/h, 22.4 mph or 19.4 knots, enough to make cycling hard work.
Flight trackers add one more wrinkle. The knots they show are usually ground speed, which includes the wind. An airliner flying at 450 knots through the air with a 100-knot tailwind shows 550 knots, or about 1,019 km/h, over the ground.