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Precision unit conversion

Speed Conversion (mph, km/h, m/s, knots)

Speed conversions come up constantly when driving abroad, reading weather forecasts, or dealing with boats and aircraft, which use nautical miles per hour (knots) rather than mph or km/h.

Reference table

ConvertResult
1 mph1.60934 km/h (0.44704 m/s)
1 km/h0.62137 mph (0.27778 m/s)
1 knot1.15078 mph (1.852 km/h)
60 mph96.56 km/h
100 km/h62.14 mph
50 mph (typical UK limit)80.47 km/h

Formulas

mph → km/h: multiply by 1.60934. km/h → mph: multiply by 0.62137 (or divide by 1.60934). Knots are based on the nautical mile (1.852 km), so 1 knot = 1.852 km/h — this is why aviation and marine speeds don't line up neatly with road speed limits.

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Common speed questions

How do I convert mph to km/h?

Multiply mph by 1.60934. So 70 mph (a common UK motorway limit) is about 112.65 km/h.

How many mph is a knot?

One knot is about 1.15078 mph, since a nautical mile (1.852 km) is longer than a standard mile (1.60934 km).

What is m/s used for?

Metres per second is the SI (scientific) unit for speed, used in physics, engineering and meteorology — for example, wind speeds are often given in m/s in scientific contexts even though forecasts usually show mph or km/h.