Rachel C, cos Lil M have like 5 pairs of crocs now! i hv 2 pairs of sizes 8/9 for her to wear prob end of yr..hahaha...then now she is wearing 4/5 Mary janes. the next size i buy is 6/7.For designs like the Kids SCutes, u can take one size smaller or exact size cos its open toe, more allowance. if i m nt wrong, the sizes represents INCHES. so now M is abt 4-5 inches..u go to crocs site, i think there is a printable size guide u can put ur bb's foot against it to check the size. Hope that helps!