Hi Heather, I read somewhere that you have to lose 15-20 pounds to change a size, and I've found that to be fairly accurate, for me at least. I started out in size 22-24 and am now 12-14 and 80 lbs. down and that is consistent with that 15-20 lbs. Of course, others may be different. I also heard that you come down a shoe size for every 25 lbs., but that hasn't worked for me, except that I am no longer wearing WW shoes, just plain W. Hope this helps!