My dog is a sliiiiightly overweight, 12 year old beagle mix and the size large has plenty of room for him. He loves it! It is a way more comfortable option for his arthritis issues. I will probably order a second bed because, when I am home, he follows me around EVERYWHERE and I’m already tired of lugging his bed from my bedroom to the living room ) It was definitely money well spent...great quality. It’s like his own personal sofa. Even the cats leave him alone while he’s on it.