In America, the standard sizes for bed sheets are twin, full, queen and king. Other bed sheet sizes are twin XL, which are longer than standard twin, and California king, which are longer and not as wide as standard king. Twin bed fitted sheets measure 39 inches by 75 inches, and the flat sheets measure 66 inches by 96 inches. Because the length of a King, Queen and Twin hardside waterbed is greater than that of standard mattresses, hardside waterbeds are sometimes distinguished as California King, California Queen and Super Single. King Waterbed: 72" x 84" Queen Waterbed: 60" x 84" Super Single Waterbed: 48" x 84" Some of our bed frame suppliers provide full size bed frames that only measure 53 inches wide. This is a big problem when we have a customer who has an old box spring. Older box springs (from the 1970's and even 1980's) measure the standard 54 inches wide, while today's newer foundations and box springs often measure only 52 - 53 inches wide.