Twin XL Mattress Size
Quick answer: a Twin XL mattress is 38 inches wide × 80 inches long — 97 × 203 cm, or 3.2 × 6.7 feet. It is exactly as wide as a regular Twin but 5 inches longer, the same length as a Queen or King, which makes it the standard bed for college dorms and tall teenagers.
Short answer: The twin xl mattress size is 38 inches wide × 80 inches long (97 × 203 cm, 3.2 × 6.7 ft) — Twin width with Queen length. It is the standard college dorm bed, the right single bed for anyone up to about 6 ft 3 in, and the building block of a Split King.
Twin XL Dimensions Chart
| Measurement | Inches | Centimeters | Feet |
|---|---|---|---|
| Width | 38″ | 97 cm | 3.2 ft |
| Length | 80″ | 203 cm | 6.7 ft |
| Surface area | 3,040 sq in | 1.96 m² | 21.1 sq ft |
The dimensions match the Sleep Foundation’s mattress sizes guide, which lists the Twin XL at the same 38″ × 80″ used by colleges nationwide.
Twin XL vs Twin
The regular Twin is 38″ × 75″; the Twin XL keeps the width and stretches the length to 80″. That extra length fits sleepers up to about 6 ft 3 in comfortably. The catch: Twin XL needs its own sheets — regular Twin sheets are 5 inches too short. Compare both in our mattress sizes chart.
If the 80-inch length is more than you need, the regular Twin (38″ × 75″) is the same width in a shorter, cheaper package.
For a buyer’s-side comparison of the longer single against its wider rival, see the Sleep Foundation’s Twin XL vs Full guide.
Who Uses a Twin XL?
- College dorms — the default dorm bed size across the US; buy Twin XL sheets for move-in.
- Tall teens — a growth-proof upgrade from a childhood Twin.
For a growing teenager, the twin xl mattress size is usually the last single bed you buy before an adult size: it fits from the early teens through college without a replacement.
- Split King beds — two Twin XLs side by side make a King (76″ × 80″), letting couples choose different firmness levels or use adjustable bases independently.
- Narrow rooms for tall adults — full adult length in a 38-inch width.
Twin XL in College Dorms: What to Know Before Move-In
The Twin XL became a dorm standard for a simple reason: colleges house adults, and a 75-inch bed is too short for a large share of them. Nearly all US college residence halls now fit Twin XL frames, but “nearly” is doing real work in that sentence — a small number of older dorms and some apartment-style housing still use regular Twins or even Fulls, so confirm the bed size on your housing portal before buying anything. For a confirmed Twin XL dorm bed you need: a Twin XL fitted sheet set (regular Twin sheets will not stretch the extra 5 inches), a mattress topper if you want comfort — dorm mattresses are famously firm, and a 2–3 inch Twin XL topper is the standard fix — and a mattress protector in Twin XL, which most colleges require or strongly recommend. Measure the under-bed clearance when you arrive: Twin XL frames are often adjustable-height, and raising the bed is free storage.
Dorm beds need Twin XL bedding, not Twin — our sheet sizes chart shows exactly where the two sizes differ.
Moving out of the dorm into a first apartment with a bigger room? The Queen size guide (60″ × 80″) is the usual next step; it keeps the 80-inch length and adds real width for one or two sleepers.
Two Twin XLs Make a Split King
Place two Twin XL mattresses side by side and you get exactly a King footprint: 76″ wide × 80″ long. That is the whole idea of a Split King. Couples pick it so each person can choose their own firmness, and it is the standard setup for dual adjustable bases, where each half inclines independently. Plan for the details: each half takes its own Twin XL fitted sheet (or one King sheet across both if you never adjust the bases separately), the two mattresses must be the same thickness so the surface sits level, and a simple bed-bridge insert fills the centre seam if it bothers you.
Minimum Room Size and Buying Sheets
A Twin XL needs the same floor width as a Twin but 5 more inches of length: with a typical frame it fits a room of 7 × 10 ft while keeping a 24-inch walkway. Sheets are the one recurring cost difference versus a regular Twin. Twin XL sheet sets are stocked everywhere dorm supplies are sold and online year-round, but in ordinary department stores the choice is thinner than for Twin or Queen — expect fewer colors and patterns, and buy a spare set at move-in time while the seasonal stock is full.
Whichever brand you choose, order by the twin xl mattress size on the label — 38″ × 80″ — and not by the words “extra long twin” alone, because a few sellers use that phrase for non-standard lengths.
Related Mattress Size Guides
- Twin Size Mattress Dimensions — 38″ × 75″, the shorter single
- Queen Size Mattress Dimensions — the post-dorm upgrade
- Mattress Size Guide & Finder — pick a size in three questions
Not sure whether a Twin XL, a Full or a Queen fits your room and height? Our mattress size guide and finder turns the answer into three questions.
Frequently Asked Questions
How big is a twin XL mattress?
38 inches wide by 80 inches long (97 × 203 cm).
Will twin sheets fit a twin XL?
No. Twin sheets are made for a 75-inch length and will not stretch over an 80-inch Twin XL. Buy sheets labeled Twin XL.
Do two twin XL mattresses equal a king?
Yes — two Twin XLs side by side are exactly a King footprint (76″ × 80″), known as a Split King.
Is a twin XL good for adults?
For a single adult, yes — it has the same length as a Queen or King. The 38-inch width is the only limitation.
Sources: Sleep Foundation — Mattress Sizes guide; Sleep Foundation — Twin XL vs Full.