Quick answer
How big is a twin XL mattress?
38" × 80" (10" thick) — A twin XL mattress is 38 inches wide and 80 inches long — 5 inches longer than a standard twin. It's the standard mattress in college dorms.
Measurements
Dimensions.
- 38"
- Width
- 80"
- Length
- 10"
- Height
Doorway fit
Will a Twin XL Mattress fit through a doorway?
Will fit through with proper technique. Smallest dimension (thickness): 10". Standard interior door: 32". Standard exterior door: 36".
Fits with room to spare
Fits with room to spare
Fits with room to spare
Mattress size comparison
| Size | Width | Length | Area |
|---|---|---|---|
| Twin | 38" | 75" | 2,850 sq in |
| Twin XL ← | 38" | 80" | 3,040 sq in |
| Full/Double | 54" | 75" | 4,050 sq in |
| Queen | 60" | 80" | 4,800 sq in |
| King | 76" | 80" | 6,080 sq in |
| Cal King | 72" | 84" | 6,048 sq in |
Measure smart
What to measure.
Four numbers decide nearly every fit check. Get these right and the rest follows.
- 01Width, depth, and height of the item at its widest points, including feet, arms, handles, and headboards.
- 02The clear opening of the space, not the frame. A 36-inch door gives roughly 32 inches once the door and stops are accounted for.
- 03The item's smallest dimension. It decides whether tilting or turning it on its side gets it through.
- 04Diagonal clearance at turns, landings, and corners, where the real bottleneck usually is.
Don't make these
Common mistakes.
Most “it didn't fit” stories trace back to one of these oversights.
- ⚠Measuring the door frame instead of the clear opening, then losing two inches you assumed you had.
- ⚠Forgetting that feet, arms, and handles add to the nominal size printed on the box.
- ⚠Treating a soft mattress and a rigid frame the same. One compresses, the other does not.
- ⚠Planning the doorway but ignoring the turn at the top of the stairs.
Go deeper
Related items and calculators.
Frequently asked
Questions we keep getting.
Will a twin XL mattress fit through a standard doorway?
Yes. At 38" × 80" × 10", the twin XL passes through a standard 32" door easily when turned on its side — the 10" thickness fits with plenty of clearance.
01Is twin XL the same length as a queen?
Yes — both twin XL and queen mattresses are 80 inches long. The difference is width: twin XL is 38" wide while a queen is 60" wide.
02Can two twin XL mattresses make a king?
Yes. Two twin XL mattresses (each 38" × 80") placed together equal 76" × 80" — the exact dimensions of a king mattress. This is a popular setup for adjustable beds.
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