As of September 2015, websites for Blair, About.com and Better Homes and Gardens show the dimensions of a full-sized flat sheet. These sheets are generally 81 by 96 inches. The accompanying standard fitted sheet is 54 by 75 inches.
Typical full-sized sheets fit a full-sized mattress, which measures the same as the fitted sheet: 54 by 75 inches. A full-sized mattress is 9 to 12 inches deep. However, mattresses with extra cushioning are thicker, which impact thes overhang of flat sheets. Premium mattresses are often 4 to 5 inches deeper. Pillow top mattress are about 20 inches thick.
In addition to size, consumers face other considerations when buying bed sheets. Thread count is important, because higher thread counts produce softer, smoother sheets. Muslin sheets have thread counts from 140 to 180. Percale sheets run higher. While typical thread counts run between 180 and 200, better quality sheets have 250 to 300. The highest thread counts of 300 to 400 indicate luxury sheets.
Sheet fabric makes a difference as well. Wrinkle-resistant cotton muslin sheets are typically softer than cotton-polyester blends. Cotton percale is comfortable and durable. Silk satin sheets provide extra warmth, but they come at a high price. Maintenance is expensive, too, because they must be dry-cleaned. Cotton jersey knit sheets feel like T-shirts. Linen sheets are traditionally the highest quality and last the longest.