Miles and Kilometres
The mile is a unit of distance used primarily in the United States, United Kingdom, and a small number of other countries. One international mile is exactly 1,609.344 metres, or approximately 1.609 kilometres. The kilometre (km) is the standard unit of distance in the metric system, used by the vast majority of countries worldwide for road distances, running events, and general measurement.
In the United Kingdom, road distances and speed limits are measured in miles, while running events are typically measured in kilometres (5K, 10K, half marathon = 21.1 km, full marathon = 42.2 km). This means UK runners frequently need to convert between the two systems.
For speed, the UK uses miles per hour (mph) for road speeds, while most of Europe uses kilometres per hour (km/h). The conversion is the same: 1 mph = 1.60934 km/h. The UK motorway speed limit of 70 mph is approximately 113 km/h.