Half marathon races are 13.1 miles or 21 kilometres, exactly half the distance of a full 26.2 miles or 42.2 km Marathon race. The average finishing time for a half in the UK is around 2:00 hours with more seasoned runners often pushing for 1 hour 30 minutes or less. This makes half marathons the perfect choice for runners looking to step up to a new challenge from 10k races and an important milestone for those on their way to running a full marathon.