Size chart - socks

the length of the foot Sock size Age
9 to 11 cm 16/18 0 to 6 months
11 to 13 cm 19/21 6 to 12 months
13 to 15 cm 22/24 12 years
15 to 17 cm 25/27 2 - 3 years
17 - 19 cm 28/30 4 - 5 years
19 - 21 cm 31/33 6 - 7 years

The age recommendation is indicative.