mph to km/h
Converting miles per hour to kilometres per hour? Multiply by 1.60934. Here is the formula and a quick reference chart.
Formula
km/h = mph × 1.60934 mph = km/h × 0.621371
Quick reference chart
| From | To |
|---|---|
| 10 mph | 16.09 km/h |
| 20 mph | 32.19 km/h |
| 30 mph | 48.28 km/h |
| 40 mph | 64.37 km/h |
| 50 mph | 80.47 km/h |
| 60 mph | 96.56 km/h |
| 70 mph | 112.7 km/h |
| 80 mph | 128.7 km/h |
| 100 mph | 160.9 km/h |
| 60 km/h | 37.28 mph |
| 100 km/h | 62.14 mph |
| 120 km/h | 74.56 mph |
When mph to km/h matters
The most common situation: you're travelling in a country that uses km/h and your car's speedometer shows mph, or vice versa. Most UK and US cars show mph as the primary unit. Most European, Australian, and Canadian roads post speed limits in km/h. The key reference points to memorise: 30 mph = 48 km/h, 60 mph = 97 km/h, 70 mph (UK motorway limit) = 113 km/h, 100 km/h (European motorway) = 62 mph.
Vehicle performance specifications often appear in both units in manufacturer datasheets. A car with a 250 km/h top speed is 155 mph. A 0–100 km/h time (the European standard) corresponds to 0–62 mph, which is how UK reviewers often report it. Sports car acceleration is frequently quoted in the UK as 0–60 mph and in Europe as 0–100 km/h — they are not identical tests.
Weather and aviation contexts also mix units. UK weather services quote wind speeds in mph, while European services use km/h or knots. Aviation weather uses knots. A 50 mph gale is 80 km/h. A 100 km/h wind is 62 mph. Hurricane and typhoon classifications use different scales depending on the issuing authority — some in mph, some in km/h — making conversion essential for comparing reports.
Running and cycling speeds also cross the boundary. A marathon world record pace is about 20.5 km/h (12.75 mph). A club cyclist averaging 30 km/h is doing 18.6 mph. A quick mental conversion: km/h divided by 1.6 gives a rough mph figure.
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Open Speed Converter →Frequently asked questions
How do I convert mph to km/h?
Multiply miles per hour by 1.60934 to get kilometres per hour. For a quick estimate, multiply by 1.6.
What is 60 mph in km/h?
60 mph equals 96.56 km/h. Multiply 60 × 1.60934 = 96.56.
What is 100 km/h in mph?
100 km/h equals 62.14 mph. Multiply 100 × 0.621371 = 62.14.
What is the speed of light in mph and km/h?
The speed of light is 670,616,629 mph or 1,079,252,848 km/h (299,792,458 m/s).
Why do the UK and USA use mph instead of km/h?
The UK and USA historically adopted the imperial system of measurement before the metric system became standard. While the UK officially converted to metric for most purposes, road speed limits and car speedometers continue to use miles per hour due to the cost and disruption of changing road signs and vehicles.