A stadium running track is usually 400 metres long when measured in the inside lane.

The longer version

One lap of a standard track is 400 metres only if you run exactly in lane one, and the distance is measured along a line set a short way out from the kerb rather than along the kerb itself. Every outer lane is longer, so starts are staggered, with the offset calculated from lane width and bend length.

The stagger is why runners in outer lanes appear to be ahead for most of a lap even when they are not. Modern tracks usually pair two semicircular bends with two straights, a geometry chosen so the same calculation works everywhere. Indoor tracks use shorter laps and tighter bends, which is why times there suffer in the turns.

Where this entry sits

Facts here look at the rules, equipment and odd histories behind familiar sports and games, from balls and rackets to cards, boards and playing fields. Expect small details about scoring quirks, stadium design and the long story of the Olympic Games. The full list sits on the Sports and Games page, where every entry is listed in order.