"My son is 4 years old and is about 43 inches & 45 lbs. I purchased a size 4-6 for him. The costume has a little room for him to grow but does not look too big. The mask/cape however is different. The cape is connected to the mask and it almost touches the ground when he is barefoot. The quality is as expected but it looks good and my child is in love with it! Also purchased the gloves and a few accessories and he is in love."