I got this for my 4 year old who has a 3 year waist size. The 4T pants are always too big for his waist but just the right length so I was hoping a belt would help. I ordered size 3T based on the size chart and it fits him perfectly. He can loosen and close the belt himself. If I could ask the creators of this belt one thing, I would make the velcro on the part of the belt (instead of the buckle) a little longer. Otherwise I have nothing to complain about and will probably order more!