I have only just started in cloth, and a friend lent me 4 small and they fitted on the largest setting, dd was just over 12 months at the time and was just on 7 kilos, I brought medium she is now 8.5 kilos at nearly 14 months, (she was sick at 12 month lost weight hence the 7 kilos). so dd would of been in smalls till around 11 month if I had started before then. I get some leg gap with mediums if not tight enough on.