Size guide Baby & Kids Socks:

Estimate Age	EU Size	UK Size	US Size
1-1.5y	18-20	1-3.5	2-4.5
1.5-2y	21-23	4-6.5	5-7.5
3-4y	24-27	7-9.5	8-10.5
5-8y	28-31	10-12.5	11-13.5
8-12y	32-35	13-3	1-3

Size guide Adult Socks:

EU Size	UK Size W	UK Size M	US Size W	US Size M
36-39	3.5-6	4-6.5	6-8.5	4.5-7
40-43	6.5-8	7-8.5	9-10.5	7.5-9