ChartStandard dimensions — nothing to enter.
A Twin mattress is 38 × 75 inches — 3 ft 2 in wide by 6 ft 3 in long, or 97 × 191 cm. It needs a room of at least 8 × 9 ft.
| Measurement | Size | Metric or area |
|---|---|---|
| Width | 38 in | 97 cm |
| Length | 75 in | 191 cm |
| In feet | 3 ft 2 in × 6 ft 3 in | — |
| Sleeping surface | 19.8 sq ft | — |
| Smallest room it fits | 8 × 9 ft | 72 sq ft |
| Comfortable room | 10 × 10 ft | 100 sq ft |
| Fitted sheet | 38–39 × 75 in | typical range |
| Flat sheet | 66–68 × 96 in | typical range |
| Comforter or duvet | 66–68 × 86–88 in | typical range |
| Pillows | 1 standard (20 × 26 in) | — |
| Rug under the bed | 5 × 8 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 Twin is 38 × 75 inches — 3 ft 2 in wide by 6 ft 3 in long, or 97 × 191 cm. It is also sold as a Single. The smallest full-length adult mattress and the default in bunk beds, day beds and children’s rooms.
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 Twin that is 8 × 9 ft at minimum and 10 × 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 Twin fitted sheet runs 38–39 × 75 in. Everything else is deliberately larger: the flat sheet at 66–68 × 96 in and the comforter at 66–68 × 86–88 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 Twin is 5 in shorter than a Twin XL (38 × 75 in against 38 × 80 in). A Twin is 16 in narrower than a Full (38 × 75 in against 54 × 75 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 Twin mattress is 38 × 75 inches, which is 3 ft 2 in wide by 6 ft 3 in long. In centimeters that is 97 × 191 cm.
A 8 × 9 ft room (72 sq ft) is the smallest that leaves 24 in down each side and 24 in at the foot. 10 × 10 ft (100 sq ft) is where it stops feeling tight and a nightstand fits on both sides.
It is built for one child, teen or adult. Split across two sleepers, a Twin gives each person 19 in of width — a single bed is 38 in for comparison.
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). 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 "Twin" is right — the mattress depth is the measurement worth checking on the packaging.
A Twin is 5 in shorter than a Twin XL (38 × 75 in against 38 × 80 in). The Twin XL needs the bigger room: 8 × 9 ft against 8 × 9 ft.
A 5 × 8 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.