I first purchased 3T and 4T for my daughter as she needs to wear school uniforms this year. She can usually fit in 3T but I can tell that she will need to move one size up soon (so I thought). I tried on the 3T when they arrived and they fell off of her. I then had to order the 2T, as I thought for sure that would fit. Well, it does not. It falls down and she is still wearing diapers. I am at a loss as to why the waist is so large. She is in the 95% for height and 100% for weight at age 2.5, these should not be too big for her. I have had to sew them smaller until I can buy another brand for her that actually fit.