I bought the 2T-4T size because my son wore 18months and I wanted to be able to bundle him up under the costume. So I figured buying two sizes bigger would be a good idea. The costume doesnt look like the picture really, and it didn't fit him well at all. It was an inch above his ankles and an inch above his wrists. I put pajamas on under the costume since I didn't have time to return the costume. I don't recommend this to anyone.