ChartStandard dimensions — nothing to enter.
A California King mattress is 72 × 84 inches — 6 ft wide by 7 ft long, or 183 × 213 cm. It needs a room of at least 10 × 9 ft.
| Measurement | Size | Metric or area |
|---|---|---|
| Width | 72 in | 183 cm |
| Length | 84 in | 213 cm |
| In feet | 6 ft × 7 ft | — |
| Sleeping surface | 42 sq ft | — |
| Smallest room it fits | 10 × 9 ft | 90 sq ft |
| Comfortable room | 12 × 10 ft | 120 sq ft |
| Fitted sheet | 72 × 84 in | typical range |
| Flat sheet | 108 × 102 in | typical range |
| Comforter or duvet | 104–110 × 94–98 in | typical range |
| Pillows | 2 king (20 × 36 in) | — |
| Rug under the bed | 9 × 12 ft | — |
Room sizes assume 24 in of clear floor down each side and at the foot as a minimum, 36 in to be comfortable. Bedding is not standardized the way mattresses are. Mattress dimensions are fixed, but sheet and comforter cuts vary between manufacturers, so these are the common US retail ranges — check the size on the packaging of the set you are buying.
The mattress itself. A California King is 72 × 84 inches — 6 ft wide by 7 ft long, or 183 × 213 cm. It is also sold as a Cal King or a Western King. Four inches narrower than a standard king and four inches longer. It is the length upgrade, and the only common size over 80 in long.
The room it needs. Bed dimensions are only half the question; the floor around the bed is the other half. The rule used across this site is 24 in of clear floor down each side and 24 in at the foot as the minimum you can live with, and 36 in as the figure that fits a nightstand and lets two people pass. For a California King that is 10 × 9 ft at minimum and 12 × 10 ft to be comfortable. Those are the same numbers the mattress size chart uses, because both come from the one rule.
Bedding, and why these are ranges. The fitted sheet is cut to the mattress, so a California King fitted sheet runs 72 × 84 in. Everything else is deliberately larger: the flat sheet at 108 × 102 in and the comforter at 104–110 × 94–98 in have to hang over the sides and the foot, which is why a comforter bought to the mattress size always looks too small on the bed. Bedding is not standardized the way mattresses are. Mattress dimensions are fixed, but sheet and comforter cuts vary between manufacturers, so these are the common US retail ranges — check the size on the packaging of the set you are buying.
How it compares. A California King is 4 in narrower and 4 in longer than a King (72 × 84 in against 76 × 80 in). A California King is 4 in narrower and 4 in longer than a Split King (72 × 84 in against 76 × 80 in). Full dimensions for every size sit on the mattress size chart.
Pocket depth still matters. These dimensions describe the mattress footprint, not its height. A fitted sheet also has to clear the mattress depth plus any topper, which is the measurement most often got wrong — the bedding size chart covers the depth bands.
A California King mattress is 72 × 84 inches, which is 6 ft wide by 7 ft long. In centimeters that is 183 × 213 cm.
A 10 × 9 ft room (90 sq ft) is the smallest that leaves 24 in down each side and 24 in at the foot. 12 × 10 ft (120 sq ft) is where it stops feeling tight and a nightstand fits on both sides.
It is built for tall adults. Split across two sleepers, a California King gives each person 36 in of width — a single bed is 38 in for comparison.
Fitted sheet 72 × 84 in, flat sheet 108 × 102 in, comforter or duvet 104–110 × 94–98 in, and 2 king (20 × 36 in). These are ranges rather than one number because bedding cuts vary by manufacturer, unlike the mattress itself. Sheets are sold by bed name, so buying "California King" is right — the mattress depth is the measurement worth checking on the packaging.
A California King is 4 in narrower and 4 in longer than a King (72 × 84 in against 76 × 80 in). The King needs the bigger room: 11 × 9 ft against 10 × 9 ft.
A 9 × 12 ft rug is the size that works in most rooms — it carries the bed and still shows floor on all three walking sides. The exact answer depends on your room, which is what the rug size calculator works out.