What is the marathon distance in miles?

The official marathon distance is 26.2 miles, or 42.195 kilometres.

The distance became standardized after the 1908 Olympic marathon in London. Organizers set the start at Windsor Castle and the finish in front of the royal box at White City Stadium, producing a course of 26 miles and 385 yards. That measurement was later adopted internationally.

Earlier marathon races did not all use exactly the same distance. The 1896 Olympic marathon, for example, covered roughly 40 kilometres. This is why historical race times cannot always be compared directly with modern performances.

A marathon is also different from a half marathon, which measures 13.1 miles. The exact metric equivalent of 26.2 miles is 42.195 kilometres, although race organizers usually round the distance in casual conversation.