Mattress Sizes & Dimensions: The Complete Size Chart (Drawn to Scale)

The short answer: a queen mattress is 60 × 80 inches, a king is 76 × 80, a California king is 72 × 84, a full is 54 × 75, a twin is 38 × 75 and a twin XL is 38 × 80. Those six are the standard US mattress sizes, and Canada uses the same ones. Everything else on this page — split kings, Olympic queens, Texas and Alaskan kings — is either a variation on those or a specialty size you’ll have to hunt for.

The chart below gives each size in inches, centimetres and feet, the total sleeping surface, how much width each sleeper actually gets, and the minimum room size the size guides we checked recommend. That “width per sleeper” column is the one most people never think about, and it’s the one that decides whether you sleep well next to a partner. A queen gives each of two adults 30 inches — only slightly wider than a crib mattress. A king gives each person 38 inches, exactly the width of a twin bed.

A note on accuracy. Mattress dimensions are nominal: brands are allowed small manufacturing tolerances, and foam beds that arrive compressed in a box can take a day or two to reach full size. If you’re fitting a mattress into a built-in frame, a platform with a lip, or an alcove, measure the frame rather than trusting the label, and leave yourself a little wiggle room. Height (thickness) is not standardised at all — it ranges from roughly 8 inches for budget foam beds to 14.5 inches for the taller Saatva Classic and close to 15 inches for some luxury hybrids — so check it separately if you’re buying fitted sheets.

Numbers in a table are easy to misread. Seen side by side at the same scale, the differences become obvious: the jump from full to queen is modest, the jump from queen to king is big, and the Alaskan king is in a different category entirely — at 9 feet square, it is wider than a queen and a twin XL laid next to each other.

Notice how the dashed six-foot line sits on every bed. On a 75-inch twin or full, a six-foot adult has three inches to spare before their feet hang off — and that’s before you account for a pillow, which pushes your head several inches down the mattress. That is why we tell anyone close to six feet tall to treat 80 inches as the minimum length, and anyone over about 6′4″ to look seriously at an 84-inch California king.

The second thing the drawing shows is that the king and California king are not “big” and “bigger.” They are two different shapes. Most people assume the California king is the largest standard mattress; it isn’t. It is longer and narrower. The overlay below makes the trade-off clear.

A twin mattress measures 38 × 75 inches (about 97 × 191 cm). It’s the standard size for children’s rooms, bunk beds and daybeds, and it is the cheapest full-length adult mattress you can buy. For a child, it is the right call almost every time: it will last from the toddler-bed transition through to the early teens, it leaves floor space for play, and bedding is cheap and everywhere.

A twin XL measures 38 × 80 inches — the same width as a twin, but five inches longer. That extra length is the whole point. It’s the standard mattress size in most US college dorms, and it’s the size we’d choose for any teenager who’s already shooting up, because 75 inches gets uncomfortable fast once someone passes about six feet. Two twin XLs side by side also make a king, which is the basis of the split king we cover below.

Who shouldn’t buy a twin? Any adult who sleeps alone but likes to sprawl. Thirty-eight inches is enough to lie still on, but a side sleeper who draws their knees up, or anyone who turns a lot in the night, will run out of room. If the room allows it, a full is a far more comfortable solo bed for an adult. And if you’re furnishing a guest room that gets used by couples a few nights a year, a full beats two twins pushed together, which inevitably drift apart and leave a gap in the middle.

A full mattress — also called a double — is 54 × 75 inches (about 137 × 191 cm). It’s 16 inches wider than a twin but exactly the same length. That combination makes it a superb bed for one adult under six feet tall, and a genuinely cramped bed for two.

Divide 54 by two and each sleeper gets 27 inches. That’s narrower than a crib mattress. Couples did sleep on doubles for generations, but most people today are taller and broader than the people those standards were set for, and the shared-bed complaints we see in owner reviews — a partner’s movement waking you, overheating, fighting over the middle — all get worse when there’s less room between two bodies. If you are buying a bed for two adults, our view is simple: don’t buy a full unless the room genuinely can’t fit a queen.

Where the full really shines is as a solo adult bed, a teen’s room upgrade, or a guest bed in a small spare room. The minimum room size most guides suggest for a full is about 9.5 × 10 feet — the same as a twin XL — so in a small apartment bedroom it can be a big comfort upgrade over a twin without stealing floor space. The one catch is length: at 75 inches it’s short for anyone over six feet. A few specialty makers sell a full XL (54 × 80), but it’s uncommon and bedding is hard to find, so tall solo sleepers are usually better off stepping up to a queen.

A queen mattress is 60 × 80 inches (about 152 × 203 cm). It is the most popular mattress size in the US, and it’s the size almost every brand quotes its prices in — including every queen price on this site. If you’re unsure what to buy, the queen is the safe answer: it fits most bedrooms (Zoma’s guide suggests a 10 × 10 foot room as the minimum), it’s long enough for most adults at 6′8″, and sheets, frames and toppers in queen are the cheapest and easiest to find of any two-person size.

The queen’s weakness is width. Thirty inches per person is fine for two people who sleep fairly still and like being close. It is not fine if one of you is a restless sleeper, if a child or a dog regularly ends up in the bed, or if either of you is a larger body. In those cases the extra 16 inches of a king is the single best upgrade you can buy — it does more for shared-bed sleep quality than most differences between mattress models.

You may also see an Olympic queen, which is 66 × 80 inches: six inches wider than a standard queen, same length. It’s a sensible compromise on paper, but it is uncommon, which means fewer mattress models, fewer frames, and sheets that you’ll usually have to buy as king and tuck. We’d skip it. If a queen feels tight, go to a king; if a king won’t fit, a standard queen with a mattress that isolates motion well is the better fix.

A standard king (sometimes called an Eastern king) is 76 × 80 inches, about 193 × 203 cm. A California king is 72 × 84 inches, about 183 × 213 cm. The king is four inches wider; the California king is four inches longer. Their total surface areas are almost identical — 6,080 square inches for the king versus 6,048 for the California king — so neither is really “bigger.” They suit different bodies and different rooms.

Pick the standard king if width is the problem you’re solving. It gives each partner 38 inches, the width of a full twin bed, which is the closest you can get to sleeping alone while sharing a bed. It is the best size for couples where one person is a light sleeper, for families where children wander in at 3 a.m., and for anyone sharing with a large dog. It’s also the size to choose if you ever want to switch to a split king for an adjustable base, since a split king has exactly the same footprint.

Pick the California king if length is the problem. At 84 inches — a full seven feet — it’s the only common size long enough for very tall sleepers to stretch out with a pillow under their head and their feet still on the mattress. It also fits long, narrow bedrooms slightly better than a king. The downsides: each partner gets 36 inches instead of 38, the selection of mattresses and frames is a little thinner, and California king sheets won’t fit a standard king (or vice versa), so be careful when buying bedding.

Both kings need real space. The size guides we checked put the minimum room at about 12 × 12 feet, and in practice you’ll want more if the bed shares the room with wardrobes and nightstands. Kings are also heavier and more expensive than queens — even a queen Saatva Rx weighs about 124 lb — so plan who is carrying a king upstairs before it arrives.

A split king is two twin XL mattresses (each 38 × 80 inches) placed side by side to make the 76 × 80-inch footprint of a standard king. A split California king works the same way with two narrower, 84-inch-long halves. You use the same king-size frame, headboard and top sheet; only the mattress (and the fitted sheets) are in two pieces.

Why would anyone want their bed cut in half? Three reasons. The first is adjustable bases: if one partner wants to raise their head to read or ease reflux while the other sleeps flat, each half needs to move independently, and a single king mattress can’t bend two ways at once. The second is different firmness preferences: with two halves you can pick a softer mattress for a side-sleeping partner and a firmer one for a back or stomach sleeper. The third is motion isolation: two separate mattresses transfer almost no movement across the gap.

The trade-off is the seam. There’s a small gap down the middle, which matters to couples who like to cuddle in the center of the bed. A bridge strip or a king-size topper over both halves mostly solves it. If neither of you needs an adjustable base and you agree on firmness, a regular king is simpler and usually cheaper. If you disagree on firmness but don’t want a seam, look at our best mattresses for couples — some beds handle mismatched partners well in one piece.

Beyond the California king are the specialty “oversized” sizes. You won’t find them in most showrooms, few mainstream online brands list them, and you’ll need a custom frame and often custom bedding. But they exist, and they solve real problems for some households.

• Alaskan king — 108 × 108 inches (9 × 9 feet). The largest size commonly made. It’s built for co-sleeping families who want two adults and one or two children in one bed. Nectar’s size guide puts the recommended room at about 16 × 16 feet.
• Texas king — 80 × 98 inches. More than eight feet long, aimed at very tall people. Note that published Texas king dimensions vary slightly between retailers, so confirm exact measurements before buying a frame. Recommended room: about 12 × 14 feet.
• Wyoming king — 84 × 84 inches. A seven-foot square: eight inches wider than a king and four longer. Good for couples plus a big dog. Recommended room: about 12 × 12 feet, though that’s tight.

Our honest take: very few people should buy one. An Alaskan king costs far more to furnish than two separate beds, it’s difficult to move, and replacing it means shopping in a tiny market. For families who co-sleep, two twin XLs or a king plus a twin pushed together (with a bridge strip) is cheaper and easier to replace one piece at a time. For tall sleepers, the California king solves the problem for anyone up to roughly 6′8″, with far more mattress choice. Treat the oversized kings as a niche — great for the right room, overkill for most.

The right size depends on four things: who is in the bed, how tall the tallest sleeper is, how big the room is, and how long you plan to keep the mattress. Here is our decision shortcut, based on the dimensions above and the room minimums from the size guides we cite.

Room size first. Before you fall in love with a king, measure the room. The minimums quoted in our chart — about 10 × 10 feet for a queen, 12 × 12 for a king — are the floor, not the target. Our own rule of thumb is that you want enough space to walk comfortably on both sides of a shared bed and at the foot, and to open every drawer and door fully. If a king leaves you squeezing sideways past a dresser, a queen is the better bed for that room.

Couples should optimise for width. Most shared-bed problems — getting woken by a partner rolling over, feeling too warm, fighting for the middle — are reduced by distance. Going from a queen to a king adds 16 inches of width, which is more than any “motion isolation” rating can buy you. If a king won’t fit, choose a mattress that isolates motion well: memory foam beds like the Nectar Premier measure far better than bouncy innersprings on this.

Tall sleepers should optimise for length. The practical rule is that your mattress should be several inches longer than you are, because your pillow moves your head down the bed. A 75-inch twin or full is fine up to about 5′10″; an 80-inch queen or king works up to about 6′3″ or 6′4″; beyond that, the 84-inch California king is the sensible choice.

Kids grow faster than mattresses wear out. A good twin will see a child through roughly a decade. If you know your family runs tall, or the room can fit it, starting with a twin XL or a full saves you buying a second bed at fourteen. And if you’re still deciding what kind of mattress to put on that frame, our budget mattress guide covers cheap beds that hold up well in kids’ rooms.

Size and mattress choice interact. A bigger bed exposes weaknesses a smaller one hides: on a king, weak edges mean the outer few inches of each side are wasted; for a heavier couple, a soft foam bed sinks toward the middle; on a bunk bed, a tall hybrid may push a child above the guard rail. These are the picks we’d pair with each situation, all drawn from the research in our reviews.

Two picks deserve a closer look. The DreamCloud Classic Hybrid is our favourite value king for couples because its edges are so strong — RTINGS scored them 9.0 — which effectively makes the bed feel wider than a mattress with soft edges of the same size. And for heavier couples, a king with a reinforced design like the Saatva HD matters more than the extra width alone; see our best mattress for heavy people guide for alternatives.

Not sure which feel you want? Our 30-second mattress finder narrows it down by sleep position, weight and budget, and our guide to memory foam vs hybrid mattresses explains which construction suits which sleeper.

Mattress size names don’t travel. A “king” in London is a different bed from a “king” in Los Angeles, and Australian queens are not quite American queens. If you’re buying in another country, importing bedding, or reading a review written for a different market, use the tables below and compare in centimetres, not names.

UK sizes run smaller than US ones. A UK double is 135 × 190 cm, very close to a US full. A UK king is 150 × 200 cm, which is roughly a US queen, not a US king. The UK super king, 180 × 200 cm, is the closest thing to an American king, but it’s about 13 cm narrower. UK beds are also mostly 190 or 200 cm long, so tall sleepers there have fewer long options than Americans do. Our best mattress UK guide covers the beds sold in these sizes.

Australian sizes include one size the US doesn’t have: the king single, 107 × 203 cm, a popular choice for teenagers that sits between a twin XL and a full. The Australian queen (153 × 203 cm) is essentially the US queen, while the Australian king (183 × 203 cm) is narrower than a US king. See our Australia guide for local picks.

Canadian sizes follow the US system: twin, twin XL, double/full, queen, king and California king, with the same inch dimensions. That makes cross-border shopping easier — though, as our Canada guide explains, several big US brands don’t ship there at all.

Picking the size is half the job. Before you click buy, check a few practical details that trip up a surprising number of people.

• Measure the path, not just the room. Boxed mattresses fit through almost any door, but traditional mattresses like Saatva’s are delivered flat and full-size. A king or California king needs to clear stairwells, landings and tight corners.
• Check your frame is the same standard. A California king won’t fit a king frame, and vice versa. Split kings use a standard king frame but need two fitted sheets.
• Mind the thickness. Deep mattresses need deep-pocket sheets. DreamCloud’s Luxe Hybrid, for example, measures close to 15 inches.
• Read the return policy. Return terms differ a lot: Saatva deducts a $99 fee, while Resident’s brands don’t refund White Glove or shipping fees. A king is the most awkward size to send back.

Finally, use the trial period. Almost every online mattress brand we cover — Saatva, DreamCloud, Nectar, Puffy and Bear — offers a 365-night trial, which gives you time to discover whether a queen really is big enough before you’re locked in. Our DreamCloud and Saatva reviews spell out the return fees and fine print for each brand.