- 100% Acrylic Our beanie sizing is true-to-size off of growth charts and the child’s age. If you your child is at the end of a cusp or you know your child is larger than average it might be best to size up rather than to size down. Size Guide Infant: 15.25 cm x 15.25 cm Toddler: 20 cm x 20 cm Youth/Small Adult: 21 cm x 23 cm Measurements above are when beanie is flat and not total size.