It is not only 6 inches. That is way too simplistic. As a previous poster noted: A full size bed measures 54"x75" or 4050 square inches. A queen size bed measures 60"x80" or 4800 square inches. So, in a queen, you are actually getting an additional 750 square inches. 750 is a bit more than 6 extra inches. And 750 square inches makes quite a bit of difference. The first thing I do before I book a hotel room is check the bed sizes. If it is anything less than a queen, we either either book elsewhere or if the kids are with us, we will make sure we have a king room and a double room. And no, it is not just in my mind. We are very uncomfortable in full size beds.