Boys clothing
						U.S. sizes	Clothing Sizes	Body sizes (cm)	Tail (cm)	Pants sizes (inch)
						XS	42	165 - 168	65 - 70	28 - 29
						S	44	169 - 172	71 - 79	30 - 31
						M	46	173 - 177	80 - 85	32 - 33
						L	48	178 - 182	86 - 93	34
						XL	50	183 - 187	94 - 99	36
						XXL	52	188 - 193	100 - 107	38
						XXXL	54	194 - 199	108 - 115	40
						Button Down Shirts (Boys)
						U.S. sizes	Chest (regular)	Chest (slimfit)	Length (back)	Arm length (short)	Arm length (long)
						S	52 cm	50 cm	80 cm	21 cm	59 cm
						M	54 cm	52 cm	81 cm	22 cm	59,5 cm
						L	56 cm	54 cm	82 cm	23 cm	60 cm
						XL	58 cm	56 cm	83 cm	24 cm	60,5 cm
						XXL	60 cm	58 cm	83 cm	25 cm	61 cm
						XXXL	62 cm	60 cm	83 cm	26 cm	61,5 cm

						Girls clothing
						U.S. sizes	Clothing Sizes	Body sizes (cm)	Tail (cm)	Pants sizes (inch)
						XS	34	155 - 162	60 - 65	25 - 26
						S	36	163 - 168	66 - 70	27 - 28
						M	37 - 39	169 - 173	71 - 75	29
						L	40 - 43	174 - 178	76 - 80	30 - 32
						XL	44 - 46	179 - 183	81 - 85	33 - 34
						Button Down Shirts (girls)
						U.S. sizes	Chest	Length (back)	Arm length (short)	Arm length (long)
						XS	45 cm	67 cm	15 cm	57 cm
						S	47 cm	59 cm	16 cm	58,5 cm
						M	50 cm	71 cm	17 cm	60 cm
						L	54 cm	72,5 cm	18 cm	61 cm
						XL	57 cm	74 cm	19 cm	61 cm

Shoe sizes

For example, a foot of length 290 mm corresponds to an internal length of 305 mm and therefore EU shoe size 46 If the foot especially wide, but can also be a shoe size of 47, 48 or even 49 may be required.

Wikipedia