King size bed dimensions
By the Sizemaven team. Checked against its sources October 14, 2026.
A standard US king, also called an Eastern king, is 76 inches wide and 80 inches long (about 193 x 203 cm). A California king is 72 x 84 inches: 4 inches narrower and 4 inches longer. A split king is two 38 x 80 inch twin XL mattresses, which together match a king. For 36-inch walkways, a king needs a room about 13 x 10 ft.
- King
- 76 x 80 in
- California king
- 72 x 84 in
- Split king
- 2 x 38 x 80 in
- King with headboard
- 80 x 86 in
King, California king and split king sizes
There are three king sizes in US stores. The standard king (Eastern king) is the widest. The California king (Western king) is the longest. The split king is a standard king made of two separate mattresses.
| Size | Inches | Centimeters | Surface |
|---|---|---|---|
| King (Eastern king) | 76 x 80 | about 193 x 203 | 6,080 sq in |
| California king | 72 x 84 | about 183 x 213 | 6,048 sq in |
| Split king | two 38 x 80 | two twin XLs | 6,080 sq in |
A king has slightly more surface than a California king, by 32 square inches. The California king gives up 4 inches of width for 4 more inches of length. Two standard twins do not make a king: at 38 x 75 inches each, they make a bed 76 inches wide and 75 inches long, 5 inches shorter than a king. A split king uses twin XL mattresses for that reason.
King and California king frame footprint
Amerisleep puts king frames at 78 to 81 inches wide and 82 to 85 inches long, and California king frames at 74 to 77 inches wide and 86 to 89 inches long. A headboard or a footboard adds more length.
| Frame type | King | California king |
|---|---|---|
| Simple frame, no headboard | 78 x 82 in | 74 x 86 in |
| Frame with headboard | 80 x 86 in | 76 x 90 in |
| Headboard and footboard, or sleigh | 82 x 90 in | 78 x 94 in |
A split king fits a standard king frame. If you use two adjustable bases, check the bases' own combined footprint instead.
What size room a king bed needs
A king needs wider walkways to feel open. Keck Furniture suggests 36 to 42 inches beside a king or California king, and the bed size tool counts 36 inches on each side as comfortable for both, with 30 at the foot. Its minimum for a tight fit is 24 inches, the same as for every bed.
With a headboard frame, a king (80 x 86 inches) needs 152 inches of wall (12 ft 8 in) for 36-inch walkways, and 128 inches (10 ft 8 in) for 24-inch walkways. A California king is 4 inches narrower, so it needs 4 inches less wall and 4 inches more depth.
| Size | Fits comfortably | Fits, but tight |
|---|---|---|
| King | 13 ft x 10 ft | 11 ft x 9 ft 6 in |
| California king | 12 ft 6 in x 10 ft | 10 ft 6 in x 9 ft 6 in |
A 12 x 12 ft room takes a king only tightly: 32 inches on each side, under the 36-inch target. Amerisleep calls 12 x 12 ft the practical minimum for a king and recommends at least 13 x 13 ft. If your room is narrow and long, a California king may fit better than a king. For a queen-sized room, see queen size bed dimensions.
Which sheets fit each king size
Fitted sheets are cut to the mattress, so king and California king fitted sheets are not interchangeable. Parachute, for example, cuts its king fitted sheet at 76 x 80 inches and its California king fitted sheet at 72 x 84 inches. A king fitted sheet is 4 inches short on a California king, and a California king sheet is 4 inches narrow on a king.
- King: king fitted sheet, king flat sheet.
- California king: California king fitted sheet and California king flat sheet.
- Split king: two twin XL fitted sheets, one for each mattress, and one king flat sheet or duvet over both (Amerisleep, Saatva).
Measure your mattress height, including any topper, and compare it with the pocket depth on the sheet listing.
Questions
Is a California king bigger than a king?
No. A California king is 4 inches longer but 4 inches narrower, at 72 x 84 inches against 76 x 80. A king has 32 square inches more surface.
Is a split king the same size as a king?
Yes. A split king is two 38 x 80 inch twin XL mattresses side by side, which together measure 76 x 80 inches, the same as a king.
Do king sheets fit a California king?
The fitted sheet does not. A king fitted sheet is 76 x 80 inches, so it is 4 inches too short for a 72 x 84 inch California king. Buy California king fitted sheets.
Will a king bed fit in a 12 x 12 room?
Yes, but tightly. With a headboard frame and two 20-inch nightstands, a king leaves 32 inches on each side, which clears the 24-inch minimum and falls short of the 36 inches that feels comfortable beside a king.
Can two twin beds make a king?
Two standard twins make a bed 76 inches wide but only 75 inches long. Two twin XL mattresses make the full 76 x 80 inch king, which is how a split king is built.
Sources
The numbers on this page come from the pages below. Brands differ, so check the size chart on the product page before you buy. Read our method