Standard fitted bed sheet sizes range from 39 by 75 inches for twin beds to 76 by 80 inches for a king-size bed. Standard flat bed sheet sizes range from 66 by 99 inches for twin beds to 108 by 102 inches for king-size beds.
The standard fitted bed sheet size for extra-long twin beds is 39 by 80 inches. For full-size and queen beds, the standard fitted sheet sizes are 54 by 75 inches and 60 by 80 inches, respectively. California king-size fitted sheets have a standard size of 72 by 84 inches.
The standard flat bed sheet size for extra-long twin beds is 66 by 102 inches. Full-size and queen beds have standard flat sheet sizes of 81 by 96 inches and 90 by 102 inches, respectively. The standard flat sheet size for California king-size beds is 108 by 102 inches, the same as for king-size beds.