Very thick! Comparable to Big Barker bed. My dog is still not used to it but he has beds everywhere. This will probably work best for him in the winter as he gets hot easy on beds here in Arizona. Placed it next to my bed and winter is when he really sleeps in the room with me. Ya my Saint Bernard is seasonable! Oh and I should say that my Saint it BIG and weighs in at 135 and the XLarge fits him well.