My son is 15 months old, 31 inches tall, 20 lbs. We ordered the 12-18 month costume and it is just perfect. It is totally adorable and fits perfect. It will definitely keep him warm on a cool October night. I'm excited to dress him up! I'm thrilled the costume isn't thin and cheapy looking. It's also a great price! I'm a very pleased new mommy! I attached a picture of my son in the image area above if you'd like to see how it fits a real kid! (It's the sideways picture because I couldn't figure out how to flip it:)