My mattresses are 16 and 18 inches. I had a thick set of of fleece sheets that I loved but they barely fit my 16 inch mattress so I ordered these. These sheets are big! They fit both my beds. On the 18' mattress this is the first set of sheets that has covered the sides and fit properly. On the 16' mattress I have enough fabric to tuck the fitted sheet under the mattress so it looks neat. The top sheet is a generous size too. Many times the top sheet is skimpy but not with this set. These sheets are bit thinner than my last pair but still soft and warm. I will be purchasing a second set. Con: This sheet set smells a like a petroleum product even after the first wash. It isn't bad but it's there. I suspect that will go away after a few washes.