Twin XL mattresses

A twin XL mattress is 38 inches wide and 80 inches long, or about 3 feet 2 inches by 6 feet 8 inches (97 by 203 cm). Depth varies by model: the Viscosoft Edge is 12 inches tall and the Edge Signature is 14, which matters when you buy fitted sheets. Those twin XL mattress dimensions give it the same length as a queen or king, so it is the narrowest standard size that still suits tall adults.

Only the length. Both are 38 inches wide, but a twin is 75 inches long and a twin XL is 80, so the twin vs twin XL mattress choice comes down to the sleeper's height. A twin suits children and shorter adults, while anyone around 6 feet or taller will use the extra 5 inches every night. The two sizes do not share fitted sheets or frames, and our bed sheet size guide compares them with every other standard size.

No. A twin frame is built for a 75-inch mattress, so a twin XL would hang 5 inches past the end with nothing under the foot of the bed. You need a twin XL mattress frame, or a platform or foundation sized for 38 by 80 inches. A foam or hybrid mattress does not need a box spring, but it does need a flat, solid surface or slats set close together, because wide gaps let the foam sag between them over time.

Choose a twin XL if you are tall and a full if you want more width. A full is 54 by 75 inches, so it gives you 16 more inches of width but 5 fewer inches of length. Anyone over about 6 feet will notice the shorter full, while a side sleeper of average height usually gets more out of the extra elbow room. Viscosoft makes its mattresses in twin XL, queen and king, but not in full.

Only for a night or two. Shared between two people, a 38-inch twin XL leaves each of you 19 inches, which is narrower than a standard crib mattress. It works for a parent lying down with a child at bedtime, but for two adults sharing every night, a queen at 60 inches wide is the realistic minimum, giving each of you 30 inches.

Most US college dorms use twin XL beds, but check with your school's housing office before you buy anything, because some still use standard twins. Dorms almost always supply the mattress, and some do not let students remove it, so a twin XL dorm mattress upgrade usually means adding a topper rather than buying a new mattress. Viscosoft dorm mattress toppers are made for that, and our article on the dorm mattress situation covers what to expect on move-in day.

Twin XL sheets, because a regular twin fitted sheet is 5 inches too short and will pull off the corners. Pocket depth matters as much as size. Most fitted sheets suit mattresses up to about 12 inches, which covers the 12-inch Edge, while the 14-inch Edge Signature needs a deep pocket of 15 inches or more. If you add a topper or a mattress protector, add its thickness to the mattress height before choosing a pocket depth for your twin XL sheets.

Two twin XL mattresses side by side measure 76 by 80 inches, the size of a standard king. Using a twin XL mattress for a split king lets each person choose their own firmness, but pick the same model for both sides, since a 12-inch Edge next to a 14-inch Edge Signature leaves a 2-inch step. You will need a king frame with center support, two twin XL fitted sheets and a king comforter over the top. A worn comfort layer on either side can be replaced without touching the other.

For an adult sleeping alone, the best twin XL mattress is thick enough to have a real comfort layer over a support core, usually 10 inches or more, with firm edges, because a 38-inch bed puts you close to the side every night. Thin foam mattresses of 6 to 8 inches are fine for a guest room but compress quickly under nightly use. The Edge Signature is 14 inches tall, its hybrid build uses pocketed coils for firmer edges, and its comfort layer can be replaced when it wears.