The standard measurements of a king-size bed mattress are 76 to 78 inches by 80 inches. These mattresses are available in various depths. The depth is the measurement from the bottom of the mattress to the top. Standard mattresses are 7 inches to 9 inches deep. Deep mattresses are those from 9 inches to 15 inches deep, and extra deep mattresses are those measuring between 15 and 20 inches.
When selecting a mattress pad, have your depth dimensions available. You can select between the standard mattress pad with a 7- to 9-inch mattress depth allowance, a deep mattress pad with the 9- to 15-inch depth allowance, or the extra deep mattress pad, which should accommodate up to 20 inches of mattress depth. This allowance should help you purchase correctly fitting sheets as well. Just make a note of the "pocket depth" on the fitted sheet measurement and choose accordingly.
The pillows for a king-size bed are generally 20 inches by 36 inches. Most king-size pillowcases will fit these pillows. If you are making your own pillowcases, measure your pillows to be sure to allow enough ease to get the pillowcases on and off. Remember that your pillows are not flat, and allow enough length and width to accommodate the girth of the pillow as well.
King-size comforters should be 108 inches by 98 inches, and the blankets should be 108 inches by 90 inches. In the case of Internet or catalog orders, check the originating point of your bedding. European bed sizes differ from American bed sizes. You may order the "king" size and the bedding may be too small if you order from Europe. Check dimensions before finalizing your order.