A quilt should measure 106 inches by 94 inches to fit a standard king-size bed. This measurement assumes a 15-inch drop on both sides and end of the bed, plus the use of a dust ruffle. No allowance is made for a pillow tuck.
The depth of the mattress should also be considered when selecting a quilt size. Mattresses can range in depth from 7 inches to 22 inches. When making a quilt, the quilting itself can reduce the finished size by 1 to 3 inches.
Commercially available bedspreads with a long drop measure 120 inches by 112 inches. Comforters with a short drop measure 104 inches by 93 inches.