Pick a mattress size, enter your room's width and length, and we will tell you whether the bed fits with enough clearance to live with it. The chart below lists every standard US bed size in inches, centimeters, and feet.
Mattress names are standardized in the United States, which makes this one of the rare sizing topics where the numbers just are what they are. A queen is 60 by 80 inches everywhere, from a luxury brand to a bed in a box. The real question is not what the sizes measure but whether the one you want leaves you a bedroom you can actually walk through. That is what the checker above answers.
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How the fit check works
We assume the headboard sits against a wall and the bed is centered on that wall, which is how almost every bedroom is arranged. That leaves three clearances that matter: the strip along each side (where you get in, get out, and put a nightstand) and the space at the foot (where you walk past). Interior designers converge on the same two numbers: 24 inches of walkway is the minimum you can live with, and 30 inches is comfortable. Below 24 inches you will sidle. The checker grades your room against those thresholds.
The formula
side clearance = (room width − bed width) ÷ 2
foot clearance = room length − bed length
Room width is the wall the headboard sits against, room length is the perpendicular wall, and the bed dimensions come from the standard chart below. Everything is compared in inches; meters are converted at 39.37 inches per meter.
Worked example
A queen mattress is 60 by 80 inches. Put it in a 10 by 10 foot room (120 by 120 inches), headboard against a wall, bed centered. Side clearance: (120 − 60) ÷ 2 = 30 inches on each side. Foot clearance: 120 − 80 = 40 inches. Both clear the 30 inch comfort line, so a 10 by 10 room carries a queen comfortably, with space for nightstands.
US bed and mattress sizes: the full chart
Dimensions are the industry standard for the mattress itself. Bed frames add 2 to 5 inches on each dimension, so if your fit is tight, measure the frame you are buying, not just the mattress.
| Size | Inches | Feet | Centimeters | Comfortable room |
|---|
| Crib | 27 1/4 x 51 5/8 | 2'3" x 4'4" | 69.2 x 131.1 | Any nursery |
| Twin | 38 x 75 | 3'2" x 6'3" | 96.5 x 190.5 | 7 x 10 ft |
| Twin XL | 38 x 80 | 3'2" x 6'8" | 96.5 x 203.2 | 8 x 10 ft |
| Full / Double | 54 x 75 | 4'6" x 6'3" | 137.2 x 190.5 | 9.5 x 10.5 ft |
| Queen | 60 x 80 | 5'0" x 6'8" | 152.4 x 203.2 | 10 x 10 ft |
| King | 76 x 80 | 6'4" x 6'8" | 193.0 x 203.2 | 12 x 12 ft |
| California King | 72 x 84 | 6'0" x 7'0" | 182.9 x 213.4 | 12 x 12 ft |
The crib dimension is the US federal standard for a full-size crib mattress. Keep it in mind for the next section.
The full bed trap
Here is the number that sells more queens than any advertisement: a full size bed gives each of two adults 27 inches of width. A crib mattress is 27 1/4 inches wide. Two people sharing a full are each sleeping on less width than a newborn gets. Couples did it for generations (the queen size was not widely marketed until the 1960s), and plenty still do, but if you have ever wondered why you wake up on a full bed feeling like you negotiated all night, that is the arithmetic. The upgrade from full to queen costs 6 inches of room width and buys each sleeper 3 inches; the upgrade from queen to king buys each sleeper another 8, which is why a king feels like a different category of sleep rather than a bigger bed.
Frequently asked questions
How big is a queen size bed?
A standard US queen mattress is 60 inches wide by 80 inches long, which is 152.4 by 203.2 centimeters, or 5 feet by 6 feet 8 inches. It is the most popular size for couples, giving each sleeper 30 inches of width. For comfortable walking space, most designers suggest a room at least 10 by 10 feet.
How big is a king size bed?
A standard US king (sometimes called an Eastern king) is 76 inches wide by 80 inches long, which is 193 by 203.2 centimeters, or 6 feet 4 inches by 6 feet 8 inches. It is exactly as wide as two twin XL mattresses side by side, which is why split king setups use two twin XLs. A room of roughly 12 by 12 feet carries it comfortably.
What is the difference between a king and a California king?
A king is wider; a California king is longer. The king measures 76 by 80 inches while the California king measures 72 by 84 inches. Unless you are over about 6 feet 4 inches tall or your room is long and narrow, the standard king is usually the better buy: you gain 4 inches of width and sheets are easier to find.
Can two adults sleep on a full size bed?
They can, but each person gets about 27 inches of width, which is narrower than a standard crib mattress. Couples slept on fulls for decades before queens took over in the 1960s, so it works, but if the room allows a queen, the extra 6 inches of total width is the cheapest sleep upgrade there is.
What size room do I need for a king bed?
A 12 by 12 foot room is the comfortable benchmark. The math: a king is 76 inches wide, so a 144 inch wide room leaves 34 inches on each side with the bed centered, which is enough for nightstands and easy walking. It can work in a smaller room if you accept clearances near the 24 inch minimum.
What is the difference between a twin and a twin XL?
Length only. Both are 38 inches wide, but a twin is 75 inches long while a twin XL is 80 inches, the same length as a queen or king. The XL is the standard in college dorms because it fits adult heights. If the sleeper is over about 6 feet tall, the XL is worth it; the 5 extra inches all go under their feet.
Are UK and EU bed sizes the same as US sizes?
No, and the names overlap confusingly. A UK double is 53 by 75 inches (close to a US full), a UK king is 60 by 78 inches (close to a US queen), and a UK super king is 72 by 78 inches (a bit smaller than a US king). European sizes run on centimeters, commonly 90 by 200 for a single and 160 or 180 by 200 for doubles. Always check dimensions, not names, when buying imported bedding.