I have purchased two of these toppers now, a California King and a King. The California King went on a normal mattress which I have had for several years and wanted a little cushion on top instead of buying a brand new mattress right now. It really makes my mattress very nice and perfect. The king went on a brand new soft memory foam mattress which my son said it still needed just some cushion on top, which he tried mine, so I ordered him the same one. He says it has made the memory foam mattress a lot better to sleep on. I have a queen bed that I purchased a different topper for but I am not as happy with that one as I am with this one so I will be buying a queen also. It's a perfect fit on both mattresses.