A mattress is the most forgiving large item to move, because it flexes, and also the easiest to size wrong, because the name (queen, king) hides a thickness that varies by inches. To buy sheets, choose a frame, or get it up a tight staircase, you need three numbers: length, width, and thickness. This guide shows how to take each one, lists the standard sizes so you can confirm what you have, and explains why a mattress can round a stair turn that a rigid item never could.
| Size | Width | Length | Typical thickness |
|---|---|---|---|
| Twin | 38 in | 75 in | 6 to 14 in |
| Twin XL | 38 in | 80 in | 6 to 14 in |
| Full / Double | 54 in | 75 in | 6 to 14 in |
| Queen | 60 in | 80 in | 8 to 14 in |
| King | 76 in | 80 in | 8 to 14 in |
| California King | 72 in | 84 in | 8 to 14 in |
Unlike a sofa or a dresser, a mattress bends. On a staircase or at a tight doorway, you do not pass the full flat width, you pass the mattress on edge and let it curve around the turn. What limits it then is the thickness against the stair width and the length against the headroom and the turn, not the flat width. A queen mattress is 60 inches wide but only 10 to 12 inches thick on edge, so it slides up a 36 inch stairwell easily as long as the turn has room for its length. Measure the thickness and the length carefully for stairs; the width matters most for the room and the bed frame.
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Frequently asked
Measure the width side to side, the length head to foot, and the thickness from the bottom edge to the top surface. Width and length tell you the size (twin, queen, king); thickness tells you the fitted-sheet pocket depth you need. Because thickness varies from about 6 to 14 inches, measure it yourself rather than assuming from the size name.
01In the US: Twin is 38 by 75 inches, Twin XL is 38 by 80, Full is 54 by 75, Queen is 60 by 80, King is 76 by 80, and California King is 72 by 84. Width and length are standardized, but thickness ranges from roughly 6 to 14 inches depending on the model.
02Usually yes. A queen is 60 inches wide but only 10 to 12 inches thick, and a mattress flexes, so you carry it on edge and bend it around the turn. The limits are the thickness against the stair width and the 80 inch length against the headroom and the turn radius, not the flat 60 inch width. Measure the thickness and length and check them against the stairwell.
03Most mattresses are 8 to 14 inches thick, with budget and kids mattresses as thin as 6 inches and luxury pillow-tops reaching 15 inches or more. Thickness is the one mattress dimension that is not standardized by size, so measure it for fitted sheets, for low bed frames, and for under-bed clearance.
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