Boy's Black Leather Shoe Leather To measure your baby's or toddler's foot, have him/her stand on a piece of paper. Mark where the tip of the big toe and the heel ends with a pencil. Measure the two marks using a centimeter ruler. Add 1.5 cm to your measurement (to account for the outsole). Use that number to determine which size fits your child best. (i.e. if his foot is 14.2, either look for that number or the next LARGER number after 14.2 that you see on the outsole measurements.)