SIZE 5: Size 5 soccer balls are ideal for players aged 12 and up, including adults and pros. They have a circumference of 27"-28" and weigh between 410 and 450 grams. The size 5 ball is most commonly used by adults and professionals. SIZE 4: Size 4 soccer balls are best for younger players, boys and girls, who use them until they are about 9 or 10 years old. Their circumferences range from 24 to 26 inches and their weights vary between 350 and 400 grams. SIZE 3: Size 3 soccer balls are designed for youth players who are just starting out. Their sizes range from 21 to 23 inches in circumference and they weigh between 280 and 320 grams. SIZE 2: Size 2 soccer balls are used by children as young as 10 or 11 years old. They are usually not used by adults because the smaller size makes them easier to handle for kids who are just beginning to learn the game. Their circumferences range from 18 to 20 inches and they weigh between 220 and 250 grams. SIZE 1: Size 1 soccer balls are for children as young as 8 or 9 years old. They are also called training balls because they give young players experience with a ball that is not too heavy nor too light.