Growing children? Bridge the gap between childhood and adulthood with a king single mattress. We have a stunning variety of king single beds for sale either as a mattress or ensemble with a king single bed and mattress. Larger than single mattresses, the king single bed is perfect for teenagers. The standard size of a king single mattress is 1,070 x 2,040 mm. Use our handy Mattress Selector to find the perfect king single bed and mattress to suit your comfort preference, health needs and price range. Browse our range below and buy your king single mattress today.