Gap Kids sizes?

[BrassicaBabe]

My kids are 7.5. I think they are average size.

Gap Kids sizes are 6-7 or 8-9. The gap shirt DS has at 6-7 is too small. But I can't believe that 8-9 is not going to swamp him.

Any clues folks? TIA

My DD is two and a half and I buy her 3-4. She's usually 2-3 everywhere else other than next which swamp her! Sizes are nuts.