Only Europe (UEFA) uses an under-21 age limit, and only for men.
FIFA, the sport's worldwide governing body, runs competitions for both men and women in the under-20 age group.
Among FIFA's continental confederations, CONCACAF and CONMEBOL hold U-20 championships for men, while the Asian Football Confederation (AFC) and Oceania Football Confederation (OFC) do not conduct U-20 championships, with their highest youth competitions for men being at under-19 level.
European countries compete for the UEFA Under-21 Championship.
To be eligible in U-21 teams it is necessary to be a maximum of 21 years old when the competition starts.