I learned this trick to figure out what shoe size(american) your boots are.
Whatever the size is say 27.5, then you add the first 2 numbers and if it is .0 its a whole and if it is .5 it is half
EXAMPLE:
27.5= 2+7 .5= 9 1/2 shoe size
29.0= 2+9 .0= 11 shoe size