The age of the players
The first thing to bear in mind when choosing an official football is the age of the players.
For players under the age of 9, which is the U-6/U-7 and U-8/U-9 age groups at club level, you should choose a size 3 ball.
For players aged 9 to 12, in other words the U-10/U-11 and U-12/U-13 age groups at club level, a size 4 ball is the right choice.
And for players over the age of 12, namely U-14s and over, you should go for a size 5 ball.