King Size Mattresses for sale. We have a wide range of kingsize & also orthopaedic & memory foam mattresses most instock for quick delivery. We have range of king size memory foam mattresses in stock ready for next day delivery. Our pocket sprung mattresses are at mega cheap prices as well. Our Mattress range will all fit a standard uk 5ft bed frames & the size of our mattresses are 5ft x 6ft 6, 150cm x 200cm.