Speed Converter
Convert speed and velocity between mph, km/h, m/s, knots, and ft/s.
Reviewed by Richard Ross · Last updated April 2026
How Speed Converter works
Key speed conversions
1 mph = 1.60934 km/h. 1 km/h = 0.621371 mph. 1 m/s = 3.6 km/h = 2.23694 mph. 1 knot = 1.852 km/h = 1.15078 mph. UK roads use mph; most of the world uses km/h.
Knots
A knot is one nautical mile per hour. 1 nautical mile = 1,852 metres. Knots are used in aviation and maritime navigation.
UK road speed limits in context
UK speed limits are set in mph: 20 mph in many urban areas (32 km/h), 30 mph in built-up areas (48 km/h), 60 mph on single-carriageway A-roads (97 km/h), and 70 mph on motorways and dual carriageways (113 km/h). When driving in Europe, the motorway limit is typically 130 km/h (81 mph) in France and Germany, so understanding the conversion prevents inadvertent speeding.
Wind speed and weather
UK weather forecasts from the Met Office typically give wind speeds in mph, but shipping forecasts use knots and meteorological data often uses metres per second. The Beaufort scale provides a qualitative description: Force 0 (calm, 0 km/h) through Force 12 (hurricane, 118+ km/h). A "moderate breeze" (Force 4) is around 20–28 km/h or 12–18 mph.
Precision and common mistakes
Speed conversions are straightforward multiplicative factors, but a common error is confusing speed (distance/time) with pace (time/distance) used in running. A runner covering 5 km in 25 minutes runs at 12 km/h (7.46 mph) — but their pace is 5 min/km (8 min/mile). These are reciprocals and cannot be converted by simple multiplication. Always check whether a figure represents speed or pace.
Frequently asked questions
How many km/h is 60 mph?
60 mph = 96.56 km/h.
How many mph is 100 km/h?
100 km/h = 62.14 mph.
What is 30 mph in km/h?
30 mph = 48.28 km/h. A common urban speed limit comparison.
How fast is a knot?
1 knot = 1.852 km/h = 1.15078 mph.
What is 70 mph (UK motorway limit) in km/h?
70 mph = 112.65 km/h. This is why UK motorway speeds appear lower than European limits of 130 km/h (81 mph) — the gap is only about 11 mph.
How do I convert m/s to km/h?
Multiply by 3.6. So 10 m/s = 36 km/h. The factor comes from 1,000 metres per km divided by 3,600 seconds per hour.
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