Children's sizes 5 -12 years old: 53, 54, 55, 56
Kid's and women's sizes: 55, 56, 57, 58, 59
Men's sizes: 57 and up.

How to measure your head
Wrap a measuring tape around head, 1.5 cm (5/8 in.) above eyebrows and ears.
If you don't have a tape measure, use a string and then measure the string. Read the measurement in centimetres or inches,
add 1 cm or 0.4 inch to the measurement,
and compare with the size chart.
If a result in between 2 sizes, go to the larger size.