Twin XL Bed Dimensions

Updated November 11, 2026 · By Serge, King Size Bed

Twin XL bed dimensions: the mattress measures 38 x 80 inches (97 x 203 cm), or 3 ft 2 in by 6 ft 8 in. It is as wide as a twin and 5 inches longer, the same length as a queen or a king. Two twin XL mattresses side by side make a king: 76 x 80 inches.

The industry guideline of the International Sleep Products Association lists 38 x 79.5 inches, with half an inch of tolerance; labels round it to 80. Across 41 mattresses sold in both sizes by five US mattress brands, the twin XL cost a median $100 more than the twin.

Twin XL bed dimensions in inches, feet and cm

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Mattress thickness is not part of the size: a twin XL can be 8 inches thick or 14, and the sheets have to match that depth.

Twin vs twin XL: what is the difference?

Only the length. Both are 38 inches wide; the twin XL adds 5 inches at the foot.

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If your feet reach the end of a twin, those 5 inches are the fix. A twin XL also leaves the same 38 inches of width, so it suits one sleeper, not two.

What the extra length costs: we compared the listed prices of the twin and twin XL versions of 41 mattresses at five US mattress brands on October 12, 2026. The twin XL cost a median $100, or 11.2%, more. The gap ran from 6.7% less to 33.4% more; in one case the twin XL was cheaper.

The European single nearest a twin XL is 90 x 200 cm (35.4 x 78.7 in): 2.6 in narrower and 1.3 in shorter. See European bed sizes vs US for every size in inches.

Twin XL vs full

A full is 16 inches wider than a twin XL, but 5 inches shorter.

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Choose the twin XL for one tall sleeper in a narrow room, the full for more width when length does not matter. For two adults, neither is generous: a full gives each person 27 inches, as our double bed dimensions guide explains.

Two twin XL mattresses make a king

Put two twin XL mattresses side by side and you get 76 x 80 inches, exactly the size of a king (see our king size bed dimensions chart, with the twin XL on the same page). That is what a split king is: two twin XL mattresses on one king frame, so each sleeper can have a different firmness, or each half can move on its own adjustable base. Our split king bed guide covers sheets and frames for that setup.

The same logic shows up under many king beds: a king box spring or foundation usually comes in two halves, each the size of a twin XL. Four of the makers we read ship their king foundation that way, as our box spring guide explains.

Any of our king bed frames takes two twin XL mattresses. Check that the frame has a center support under the seam, and see the frame's outside size on its product page.

Twin XL bed frame size

A frame is always bigger than its mattress. We found too few twin XL frames with listed sizes to give a median. For twin frames, the median of 66 models at a US online furniture store was 42.1 x 80.4 inches, about 4 inches wider and 5 inches longer than the mattress. A twin XL frame built the same way would measure about 42 x 85 inches; that is our estimate, so check the outside size on the listing.

A twin frame will not take a twin XL mattress: the mattress is 5 inches too long.

Comparing a twin XL with the other US sizes? Our bed frame sizes chart lists every mattress size with the real outside size of the frame.

How big a room do you need for a twin XL?

With a frame of about 42 x 85 inches (our estimate above) and our rule of thumb of 24 inches of walkway, not an official standard:

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Compared with a twin, a twin XL takes 5 inches more of the room's length and the same width.

Twin XL sheets and bedding

• Sheets: buy twin XL. A twin fitted sheet is 5 inches too short for the mattress. Of the sheet sets sold in twin XL by the five brands we read, all 9 were sold as their own twin XL size.
• Duvets, comforters and quilts: usually one size for both. Of 28 sold in twin XL by the same brands, 26 came as a single "Twin/Twin XL" size, because a cover that hangs over the sides does not need the exact length.
• Mattress protector: twin XL, sized for the depth of your mattress.

Sheets follow the depth too: the average mattress thickness across 223 US models is 11.3 inches, and half of them are 10 to 14 inches thick.

Who is a twin XL for?

• One tall sleeper in a room too narrow for a full or a queen.
• College dorms, many of which furnish twin XL beds: check the size with the college before you buy sheets.
• A split king, two twin XL mattresses on one king frame, for couples who want different mattresses or adjustable bases.

Mattress sizes: US labels and the dimensional guideline of the International Sleep Products Association. Prices: listed prices of the twin, twin XL and full versions of the same mattresses at five US mattress brands, read on October 12, 2026 (41 twin and twin XL pairs, 42 twin XL and full pairs). Bedding: how 37 sheet sets, duvets, comforters and quilts sold in twin XL by the same brands are sized. Frame figures: listed outside sizes of 66 twin bed models sold by a US online furniture store, read on September 29, 2026; the twin XL frame size is our estimate from them. Room chart: 24 inches of walkway, our rule of thumb.

Bigger sizes: full vs queen bed and queen size bed dimensions.

Also useful: our Twin Bed Dimensions guide.