Mondo (cm)	Men (US)	Women (US)	Europe	U.K.
15	8 (youth)	-----	25	7
16	9 (y)	-----	26	8
17	10 (y)	-----	27	9
17.5	11 (y)	-----	28	10
18.5	12 (y)	-----	29	11
19.5	13 (y)	-----	30.5	12
20	13.5 (y)	-----	31	13
20.5	1	-----	32	13.5
21	2	-----	33	1
21.5	3	-----	34	2
22	4	5	35	3
22.5	4.5	5.5	36	3.5
23	5	6	36.5	4
23.5	5.5	6.5	37	4.5
24	6	7	38	5
24.5	6.5	7.5	38.5	5.5
25	7	8	39	6
25.5	7.5	8.5	40	6.5
26	8	9	40.5	7
26.5	8.5	9.5	41	7.5
27	9	10	42	8
27.5	9.5	10.5	42.5	8.5
28	10	11	43	9
28.5	10.5	11.5	44	9.5
29	11	12	44.5	10
29.5	11.5	-----	45	10.5
30	12	-----	45.5	11
30.5	12.5	-----	46	11.5
31	13	-----	47	12
31.5	13.5	-----	47.5	12.5
32	14	-----	48	13
32.5	14.5	-----	48.5	13.5
33	15	-----	49	14
33.5	15.5	-----	50	14.5
34	16	-----	51	15

 

Boot sizes may vary slightly by manufacturer so be sure to check the sizing for individual models.