My 2 year old is small for his age, wears clothes for 12 to 18 months and 24 months depending on brand. As other reviewers have suggested, I went up a size and settled on the 3T. I've included a few photos, one showing the amount of shrinkage (machine washed and dried) and the other with a pair of 18 month old leggings for size comparison. The belt is almost the same size on all three leggings in the second photo.
Slaixiu Leggings Fleece Printing GP777 3P B 130 Girls' Clothing and Leggings
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Thermajane Girl's Cozy and Comfy Thermal Underwear Long Johns Set with Fleece Lining
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