The medium fit like a medium in my opinion. I'm a 27/28 waist and I could have honestly gone with the small. There is a generous amount of room for synching with the privacy material behind the laces. I'd say arounder 3". If you want it to do what it's supposed to do and synch you in then just order the size you normally are. You can loosen and tighten this way and with the small you have the option vs the med were you really dont.  The trick with these things is to get a size that you can -pull in- !!! Otherwise you're left without the room to do so. :( I've got about an inch to play with before I can't tighten it anymore. So if I loose any inches around my waist this probably won't work for me and the clasps won't stay locked. :(