I have these in a size 11-12 for my average size 11. I bought him a pair of sweatpants from this brand in the same size and they fit him perfectly. However, this sweatshirt seems to run small as it's a bit tighter around it. I think he can benefit from it in the spring, but I don't expect it to suit him in the fall. I would go up a size if possible unless you want a snug fit.
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