How thick is a mattress?

A mattress is typically 12 in (30 cm) thick. That is the median of 45 adult mattresses on sale in October 2026 from Casper, Tuft and Needle, Zinus, Avocado and IKEA US, and 21 of them fall between 10 and 12 in (25 to 30 cm). The figure usually quoted is 10 to 12 in, and planning guides often say 12 to 14 in. Both describe the direct-to-consumer brands. Neither describes IKEA, whose nine US mattresses run from 3 7/8 to 11 in and centre on 7 7/8 in (20 cm). Thickness then decides three things buyers find out late: which sheets fit, how high the bed stands, and whether the mattress can go on a top bunk at all.

Thickness, profile and H: one number, measured cover to cover#

IKEA writes thickness, Tuft and Needle writes profile, and Casper, Zinus and Avocado give it as the H in a W x L x H line. All three mean the distance from the underside of the cover to the top, at the edge, with the mattress fully expanded and nobody on it.

A measured mattress can disagree with its listing. It may not have finished expanding: Zinus says a rolled mattress can take up to 72 hours to reach full height. A pillow-top counts: Avocado's Vegan mattress is 11 in (28 cm) as a tight top and 13 in (33 cm) with its pillow-top. Measure at the side, where a sheet's elastic has to grip.

Length and width are in bed sizes and room sizes, the frame's margin in bed frame vs mattress dimensions, and terms such as bunkie board in the glossary.

45 mattresses from five makers, thinnest to thickest#

Every current adult mattress from five makers whose product pages state a height. A model sold as a tight top and a pillow-top counts twice, once per height. Children's mattresses and models with no stated height are left out.

Grouped into bands, the 45 look like this:

The top end has been coming down: Avocado says its Luxury pillow-top was cut from 17 to 14 in and its box-top from 19 to 15 in.

Why the median is 12 in: a support core plus 2 to 4 in of comfort#

A mattress is a support core, a comfort layer and a cover, and the core is the larger part. Avocado publishes enough of two build-ups to add them. Its Latex mattress is 3 in (8 cm) of Dunlop latex over a 6 in (15 cm) Talalay base: 3 + 6 = 9 in, its listed height. Its Hybrid is 8 in (20 cm) pocket coils under a 2 in (5 cm) latex comfort layer, 8 + 2 = 10 in, with the wool and the quilted cover making up the rest of its 11 in (28 cm). The pillow-top version is 13 in, and the extra 2 in is all comfort material.

That is the pattern in the bands. A 6 to 8 in core with almost nothing on top is the under-8 in group, the mattresses IKEA sells for daybeds, trundles and bunks. Add 2 to 4 in of comfort material and the result is 10 to 12 in. The 13 to 15.5 in models add a pillow-top or box-top to the same cores: the extra inches buy comfort depth, not support.

12 in online, 7 7/8 in at IKEA: two meanings of "standard"#

The 36 mattresses from the four online brands have a median of 12 in, and only two are under 9 in. The nine IKEA US mattresses have a median of 7 7/8 in, and the thickest, VÅGSTRANDA at 11 in, would sit in the lower half of the online set.

IKEA builds thickness in two parts. Several US listings sell a mattress and a topper as one product: VALEVÅG with NISSEHOLM or NORDBERGET, VESTERÖY with NÄSFJÄLLET. IKEA's US toppers are 1 5/8 to 2 3/4 in (4 to 7 cm). VALEVÅG at 9 1/2 in plus NISSEHOLM's 2 in comes to 11 1/2 in (29 cm), back in the middle of the online range. So "standard" means 12 in online and about 8 in at IKEA, and the trouble starts when one meets the other's sheets or frames.

Fitted sheets: a 10 in pocket fits 17 of the 45#

A fitted sheet is sold for a maximum mattress thickness, its pocket depth. The corners have to reach under the mattress, so the pocket must exceed the whole stack: mattress, topper and protector.

IKEA's DVALA stops at 10 in, thinner than IKEA's own VÅGSTRANDA or VALEVÅG with any topper. Casper's sheets stop at 14 in, the exact height of its Dream Max and Snow Max, leaving nothing for a protector. A 3 in topper on a 14 in mattress is 17 in (43 cm), past Casper's standard protector and Parachute's sheet; Casper sells an 18 in protector for that case.

The top bunk: 5 1/8 in, and only 2 of 45 fit#

On a bunk, mattress thickness is a safety dimension. The US bunk bed rule, 16 CFR 1513, requires the top edge of each upper guardrail to be at least 5 in (130 mm) above the top surface of the mattress, measured with a mattress of the maximum thickness the manufacturer specifies. So the maker marks a maximum, and the rail is designed around it. IKEA's US bunk and loft beds state theirs:

Of the 45 adult mattresses, two are 5 1/8 in or less: ÅGOTNES at 3 7/8 in and ÅSVANG at 4 3/4 in. IKEA also sells VANNAREID, a twin-only spring mattress at exactly 5 1/8 in. Eight of the 45 fit MYDAL's 8 1/4 in. None of the 36 online-brand mattresses fits a 5 1/8 in bunk; the thinnest, Tuft and Needle's Kin 6, is 7/8 in too thick.

Cribs work the same way, with the rail fixed by a maximum mattress thickness; see crib dimensions and clearances. The next bed's sizes are in kids bed sizes by age.

Bed height: deck plus mattress puts the top at 24 to 28 in#

The sleeping surface is the mattress plus whatever it rests on, called the deck here: the slats of a platform, or the top of a foundation in a frame. Foundations are sold by height. Tuft and Needle's Box Foundation is 7 in (18 cm), and Avocado's comes as a 3.5 in (9 cm) low profile or a 7.25 in (18 cm) standard. Thuma's bed frame is 13 in (33 cm) high with 9 in (23 cm) clear underneath.

The site's nightstand dimensions put most mattress tops at 24 to 28 in (61 to 71 cm) and set the nightstand to match. Working back from that band gives the deck each thickness needs:

It runs the other way when the frame is fixed. A 12 in mattress on a 7 in foundation held 7 in off the floor is 26 in (66 cm) high. A 14 in mattress makes it 28 in, the top of the band, and a 3 in topper on that makes it 31 in (79 cm), well above a 24 in nightstand.

Every inch of mattress also comes off the headboard visible above the pillows, the datum headboard heights and sizes works from. IKEA's MALM, SONGESAND, TONSTAD and IDANÄS have adjustable bed sides, and IKEA warns that a very thick mattress may cover part of the headboard.

Sizes: what a queen measures when the maker measures it#

Size classes are nominal, and makers that publish measured sizes list something slightly different.

Avocado lists its full at 54 x 75 in, so Casper and Avocado disagree on a full by an inch of width. Lengths are never over nominal, and only IKEA's twin widths are, by a quarter inch. Between queen and king the gap stays 16 in (41 cm) of width in every column, as queen vs king works through.

Weight, delivery, and where the numbers stop#

Thickness does not predict weight; material does. Casper's 11 in Cloud One queen is 66 lb (30 kg). Avocado's 9 in Latex queen is 128 lb (58 kg), nearly twice as heavy at two inches thinner, and its 13 in Eco plush queen is 132 lb (60 kg). Tuft and Needle's queens run from 74 lb for the 12 in Original II to 118.5 lb for the 15 in Mint Luxe. A boxed mattress still has to clear the doors and the turns of the stairs, which is where measuring the delivery path starts.

These numbers stop applying in three places. Children's mattresses were left out; Avocado's Kids mattress is 7.5 in (19 cm), and cribs have their own federal limit. Adjustable bases set their own deck height, so use the base maker's figures. Mattresses outside the set: five makers are a sample, not a census, and the listing for the product you buy outranks the median.

Room clearances are measured from the frame, in bedroom clearances and the bedroom layout checker, with the rest in bedroom dimensions and furniture dimensions. Sources are listed below under the site's standards, codes and sources policy.

Six checks before you buy a mattress, sheets or a bunk#