The first world record in the 400 m for men (athletics) was recognized by the International Amateur Athletics Federation, now known as World Athletics, in 1912. The IAAF ratified Charles Reidpath's 48.2 performance set at that year's Stockholm Olympics as a world record, but it also recognized the superior mark over 440 yards (402.34 metres) run by Maxie Long in 1900 as a world record. Through 2021, World Athletics has ratified 24 world records in the event. The following tables show the world record progression in the men's 400 metres, as ratified by World Athletics.