Bedding manufacturers usually offer one size of king flat sheet for the two most common king mattress sizes. A typical king flat sheet measures 108 inches wide by 102 inches long. This size fits both the standard king mattress, which is 76 inches wide by 80 inches long, and the California king mattress, which measures 72 inches wide by 84 inches long. Sheet sizes are not necessarily standard; some companies offer king-size flat sheets that measure up to 115 inches long.
Mattress Size and Depth Variations
In addition to width and length, mattress depth -- the vertical height of the mattress when it is lying flat -- can affect sheet sizing. The sheet measurements supplied should fit mattresses up to 20 inches deep. However, some extra-depth mattresses can be as much as 24 inches deep. Some mattress suppliers also make oversized king beds, which are proprietary and non-standard sizes. If you have an extra-depth or oversized mattress, contact the manufacturer to find a source for sheets that will fit your bed.
Yardage in King Flat Sheets
For the do-it-yourself decorator, flat sheets can provide fabric yardage to make items such as curtains, tablecloths or slipcovers. In addition, you can make your own flat sheets from fabric yardage. In either case, it is useful to know approximately how many yards of fabric it takes to make a king flat sheet:
- A king flat sheet that's 108 inches wide by 102 inches long, turned sideways, yields about 3 yards of fabric width-wise; that is, 102 inches wide. Used lengthwise, the same size sheet yields about 2 3/4 yards of fabric that is 108 inches wide.
When using a sheet to make other projects, you'll need to subtract the hems and side edges, which are usually trimmed off before cutting out your pattern. However, some items such as curtains can incorporate the existing sheet hem as one of the finished edges.
To make your own sheets from fabric yardage, you should purchase 1 to 2 extra yards to allow for hems, seams and matching patterns. You can find sources of extra-wide sheeting fabric online, or ask a fabric store if they can order suitable material. Another option is to seam two lengths of 54-inch-wide fabric down the middle of the sheet. The result is slightly less than 108 inches wide after the seam is completed, but it will serve for the narrower California king mattress.