ChartStandard dimensions — nothing to enter.
Twin bedding is not one size. The fitted sheet matches the mattress at 38–39 × 75 in, the flat sheet is 66–68 × 96 in and the comforter is 66–68 × 86–88 in — each is cut for a different job.
| Piece | Size | Why that size |
|---|---|---|
| Fitted sheet | 38–39 × 75 in | Matches the mattress exactly and grips underneath |
| Flat sheet | 66–68 × 96 in | Wide enough to tuck on both sides and the foot |
| Comforter or duvet | 66–68 × 86–88 in | Hangs over the sides so the bed looks made |
| Duvet cover | 66–68 × 86–88 in | Cut to the comforter, not to the mattress |
| Pillows | 1 standard (20 × 26 in) | Sized to sit across the 38 in width |
| Mattress | 38 × 75 in | The measurement everything else is derived from |
Every piece except the fitted sheet is deliberately bigger than the mattress — that overhang is the whole design. 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.
Start from the mattress. A Twin mattress is 38 × 75 inches (97 × 191 cm), and the fitted sheet is cut to match at 38–39 × 75 in. Everything else on the bed is sized off that footprint, which is why bedding is sold by bed name and not by inches.
The flat sheet is wider on purpose. At 66–68 × 96 in it carries roughly 14 in of tuck down each side. Buy one cut to the mattress width and it pulls out every night — the extra fabric is doing a job.
Why every figure here is a range. 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 comforter is wider still. 66–68 × 86–88 in lets the cover hang over the sides of the mattress rather than stopping at the edge. On a bed with a thick mattress or a topper, size up rather than down: a comforter that stops short reads as too small from across the room, and no amount of arranging hides it.
Depth is the measurement that goes wrong. The footprint of a fitted sheet is fixed by the size name, but the pocket depth is not. Standard pockets take a mattress up to 14 in, deep pockets 15 to 18 in, extra-deep above that — and a topper counts towards the total. The bedding size chart covers the bands.
The room the bed sits in. If you are still choosing the bed rather than the sheets, a Twin needs at least 8 × 9 ft of floor. The Twin bed size page has the dimensions and clearances in full.
Fitted sheet 38–39 × 75 in, flat sheet 66–68 × 96 in, comforter or duvet 66–68 × 86–88 in, and 1 standard (20 × 26 in). The mattress underneath is 38 × 75 in.
No, and it should not be. The mattress is 38 × 75 in and the comforter is 66–68 × 86–88 in so that it hangs over the sides. Matching the two exactly leaves the bed looking undressed.
Only if the pocket depth allows it. The 38–39 × 75 in footprint is fixed, but pockets run from 14 in standard up to 22 in extra-deep. Measure the mattress from the seam at the top to the seam at the bottom, add any topper, and buy to that.
1 standard (20 × 26 in). That is what sits across the 38 in width without crowding or leaving a gap.
Yes — a duvet cover is cut to the comforter it holds, so both are 66–68 × 86–88 in for a Twin. Neither is cut to the mattress.
The flat sheet and comforter have some tolerance because they are meant to overhang. The fitted sheet does not: it is cut to 38–39 × 75 in and will either not reach or will not stay on.