Futon Mattress Sizes

The three systems, side by side

Three things fall out of that table immediately.

The bifold futon mattress is the well-behaved one. The DHP 8-inch pocket coil full is 75 by 54 inches, which is a standard full to the inch. If your futon frame was built for a full futon mattress, standard full sizing is what you are shopping for, and your existing full sheets will fit.

The floor futon is five inches longer than you expect. MAXYOYO’s whole range runs 80 inches long — twin, full, queen and king alike. A floor-futon full is 54 by 80, not 54 by 75. That extra five inches is good news for anyone over 5 ft 10 in and bad news for a fitted sheet bought for a full bed, which will be five inches short.

The sofa-bed mattress is smaller than everything. Fifty-eight by seventy-two inches is two inches narrower and eight inches shorter than a bedroom queen. It is not a defective queen; it is the size sleeper-sofa decks are built to, because the mattress has to fold into the sofa body. The full story on that system is in sleeper sofa mattress sizes.

What fits a futon frame

A futon frame is built around one mattress size and will not take another. Full is the common one in the United States, twin is the dorm and chair-bed size, and queen frames exist but are much rarer. The frame decides; the mattress follows.

The second constraint is depth, and it is the one that catches people who have correctly matched the length and width. A bifold frame has to close around the mattress, and eight inches of pocket-coil mattress is a genuinely stiff fold — the DHP full weighs 59 lb. Several frames in adjacent categories publish a hard ceiling: the Novogratz Bushwick daybed states a maximum of 8 inches, as does the Dream Solutions pop-up trundle, where exceeding it means the two sleeping surfaces no longer sit level.

The third is the carton, which almost nobody checks. The DHP full ships rolled in a carton measuring 59 by 13 by 13 inches. That is a long box to get up a stairwell, and it is the only dimension that matters on delivery day.

Floor futons are sized as bedding, not as furniture

A Japanese floor futon — a shikibuton — is not sized to a frame, because there is no frame. It is sized to a sleeper and to the floor, which is why the whole range is 80 inches long regardless of width. MAXYOYO publishes twin at 39 by 80, full at 54 by 80, queen at 60 by 80 and king at 78 by 80.

The variable that moves in this category is thickness rather than footprint. MAXYOYO sells the same mattress in 4, 4.5, 6 and 8 inch versions, and the gap between the 4-inch and the 8-inch is the difference between a floor you can feel and a bed. Four inches on tile or laminate is four inches, and the manufacturer’s own framing is that side sleepers and heavier adults will feel the floor through it.

So the sizing decision in this system is two-dimensional: pick the width from the sleeper, pick the thickness from the floor and the sleeper’s weight. The field is covered in the best Japanese floor futons, and the position-specific version of the thickness question is in the best futons for side sleepers.

Tri-fold mattresses use a fourth set of names

Folding foam mattresses — the kind that stand in a closet in three layers — publish their own size names, and two of them do not exist anywhere else in bedding. Milliard’s 6-inch tri-fold is sold as Single at 75 by 25 inches, Cot at 75 by 31, Twin XL at 78 by 38, Full at 75 by 52 and Queen at 78 by 58.

Read those against the first table and the pattern is clear: a tri-fold “full” is two inches narrower than a standard full, and a tri-fold “queen” is two inches narrower and two inches longer. Single and Cot are narrower than any standard mattress size — 25 and 31 inches against a twin’s 39 — which makes them a floor-sleeping or camp-cot format rather than a bed one.

How to get the size right in four measurements

One: measure the deck, not the old mattress. On a futon frame, measure the slatted platform corner to corner with the frame flat. On a sleeper sofa, pull the deck out and measure the metal frame the mattress sits in. Old mattresses compress and shrink at the edges, so measuring the thing you are replacing is how people buy one size too small.

Two: find the frame’s stated maximum depth. If the manufacturer publishes one, it is a ceiling and not a suggestion, especially on anything that has to fold or rise level with another surface.

Three: identify the system before the size. Bifold futon, floor futon, tri-fold or sofa-bed replacement. Four products can all say “full” and no two of them share both dimensions.

Four: check the carton against the route in. A rolled full futon mattress ships in a box around five feet long. Measure the tightest turn on the stairs.

If this is a replacement for a sleeper sofa rather than a futon frame, the dedicated page is the best sleeper sofa replacement mattresses. If it is for a daybed or a trundle, the depth ceilings matter more than the width and the page for that is what size mattress for a daybed. And if you have not bought the frame yet, the mattress-first way round is in the best futon mattresses.