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Bed Sizes & Mattress Dimensions - Sizing Guide | Mattress Firm

Mattress Sizes And Dimensions: A Bed Sizing Guide

Our mattress size guide outlines the different sizes of beds and their dimensions to help you find the bed size that will serve your bedroom needs best.

Mattress Sizes and Dimensions Chart

Mattress Size Dimensions in
Dimensions in
California King72" X 84"183cm X 213.5cm
King76" X 80"193cm X 203.5cm
Queen60" X 80"152.5cm X 203.5cm
Full54" X 75"134.5cm X 190.5cm
Twin XL39" X 80"96.5cm X 203.5cm
Twin39" X 75"96.5cm X 190.5cm
Crib27" X 52"68.5cm X 132cm
Mattress Size Chart
What mattress size is right for you?
Choosing what size mattress to buy isn’t easy, especially considering the array of choices available. Mattress size is an individual preference, but understanding specific dimensions and your own expectations will help you narrow down the bed size that will serve your needs best. When you’re considering which bed size to buy, some factors to consider include whether or not you sleep with a spouse or partner, if children and pets share your bed, whether you’re on the taller or shorter side and how large your bedroom is. Record bedroom dimensions before you shop to give yourself an idea of the space you have, and do some research so you’ll feel confident when you’re ready to buy.
Cal King size
Approximately 72” X 84”

California king-size mattresses take approximately four inches of width from a conventional king-size bed and add it to their overall length. If your feet have always hung off the edge of a mattress, a Cal king bed will provide you with the length you need while still having more width than a queen-size bed.

Best for
Taller sleepers, especially those over six feet, who need a longer mattress to sleep comfortably. With slightly narrower dimensions, a Cal king mattress size is best for certain rooms where a wider king-size mattress may not fit.
King size mattress
Approximately 76” X 80”

Offering a luxurious amount of space, king mattress sizes give couples the equivalent of a twin XL mattress size to themselves. King-size beds sit atop two twin box springs pushed together to make maneuvering an entire king bed into a room much easier. King-size mattresses are wider but shorter than California king-size mattresses.

Best for
Couples or single sleepers who don’t want to compromise on sleeping area, especially if they share bed with large pets or young children and find a queen-size mattress lacking in space. Most master bedrooms can accommodate a king-size bed.
Queen size mattress
Approximately 60" X 80"

Queen bed size dimensions are the most popular because they are perhaps the most versatile bed size. Queen mattresses give sleepers enough space to sleep comfortably while still fitting in smaller bedrooms.

Best for
Adult couples or single sleepers who are looking for a mattress size they won't outgrow but that is not as tall or wide as a king bed.
Full size mattress
Approximately 54" X 75"

Full-size mattresses provide a good compromise between twin and queen-size mattresses. A full bed size offers a good amount of space for single sleepers and is a good bed size option for a guest bedroom.

Best for
Teens who have outgrown their childhood beds and individuals who have smaller apartments looking for an economical price and size.
Twin XL mattress size
Approximately 39" X 80"

As the standard bed size for college dorm rooms, a twin XL mattress gives students room to stretch out but doesn't offer any more width than a conventional twin-size mattress. Although this mattress is easy to move around, adults prefer a larger bed size once circumstances allow.

Best for
Taller kids and students living in college dorms.
Twin size mattress
39" X 75"

Twin mattresses, also known as single mattresses, are slim in size, which makes them easy to fit side by side in shared kids bedrooms or stacked as bunk beds. Twin beds are the size most kids sleep on through childhood and are easy to move around.

Best for
Solo sleepers from toddlers and teens to adults who are shorter than six feet.
Crib size mattress
27" X 52"

These crib mattress size dimensions are widely accepted to be the standard across the U.S., so this bed size will fit any standard crib. For safety reasons, crib mattresses are firmer than adult mattresses and most commonly foam or innerspring mattresses.

Best for
A crib mattress is the right bed size for your baby's first bed and will fit most babies until toddlerhood.
Personalized Sleep
What is a Split-King Mattress?
A Split-King mattress is made up of two Twin XL mattresses placed side-by-side measuring a total of 76" by 80". This helps deliver a more personalized feel for couples who have different bed type preferences and sleeping positions. To order or learn more about split-sizes, please contact our Sleep Experts® by call or chat.

Frequently Asked Questions

What's the difference between a twin and single mattress?

The words “twin” and “single” are often used interchangeably to describe the same size mattress, but there is no difference between the two. While “twin” is considered the standard name in the U.S. for a mattress that measures 39 inches by 75 inches, other parts of the world favor the term “single” for a bed with the same dimensions. Wherever you go, 39” x 75” is the standard size for a bed designed for one person.

Is a full-size bed the same as a double?

Yes, full-size beds and double beds are the same thing. Both terms refer to mattresses measuring 54 inches by 75 inches. Though the word “double” would suggest that a full or double bed is twice the size of a twin/single mattress, that’s not the case. A full mattress is 15” wider than a twin bed, but the same length. Double and full can still be used interchangeably, but double is an older term, and mattress manufacturers have mostly replaced it with the word full. Mattress Firm also carries futons that vary in thickness and sit on a full-size bed frame.

Is there a difference when describing the sizes of beds versus mattresses?

For the most part, no. Bed and mattress are terms used interchangeably for one another, but bed can sometimes suggest a set instead of a single mattress. The term bed could mean a mattress and box spring, or mattress, bed frame, box spring, and headboard. It’s unlikely that a manufacturer would list dimensions that included accessories, because their sizing isn’t standardized, and most mattresses can be paired with a variety of compatible accessories and generally aren’t sold as sets.

What size mattress do two side-by-side twin beds make?

Technically, two twin beds are just two twin beds. However, at 39 inches by 75 inches, two twin or twin XL beds provide close to the amount of space of a king or California king mattress, which measures 76 inches wide by 80 inches long. Conveniently, these close measurements allow manufacturers to support king and California king mattresses using two side-by-side twin or twin XL box springs, so customers don’t have to worry about trying to drag a 76 inches wide by 80 inches long box spring—which won’t bend the way a mattress will—up a flight of stairs to a master bedroom.

What about the other sizes of mattresses, like Texas or super king?

In addition to standard mattress sizes, over the years, several “specialty” mattress sizes have been created. Not widely sold and often only made by certain manufacturers in a small selection of models, these mattress sizes may be worth exploring if you don’t feel standard options serve your needs. However, note that as a result of their rarity, specialty mattresses can be difficult to find accessories and bedding for, so factor that into your decision before you buy.

Is a full-size bed big enough for two people?

It depends. A full mattress provides each person with 27 inches of space, which is the equivalent width of a crib. If you’re considering a full bed because you have limited space or budget constraints, test one out with your partner and decide if the sacrifice in personal space and length makes sense. For shorter sleepers, it might, but taller sleepers may find a full bed’s 54 inches insufficient. Mattresses aren’t one size fits all, so focus on what size will work best for you.

What’s the most popular mattress size?

The most popular mattress size in the U.S. is a queen. For many, the queen mattress balances adequate space for two people with a size that’s easier to move through narrow doorways and staircases. It also strikes a middle ground in terms of budget compared to pricier king mattresses. Don’t let the masses determine what size mattress you buy, though—do your research, and always consider the factors that matter most to you before you make a decision.

What’s the largest mattress available?

If you thought a traditional king was big, think again. The largest mattress size on the market is appropriately named the Alaskan king, measuring an opulent 108 inches wide by 108 inches long. If you have the space for this mattress size, you and your partner will each enjoy 54 inches of space—the equivalent of an entire full mattress—to yourselves. Looking for more space but not sure the Alaskan king is for you? Read more about why switching to a traditional king might be the right choice instead.

What are the dimensions of RV mattresses?

The RV Three-Quarter, which measures 48 by 75 inches, makes it smaller than a full but bigger than a twin. It’s great for smaller vans and perfectly accommodates two small kids.The RV Short King, measures 72 by 75 inches and sleeps two to three people without taking up too much room. The RV King, measures 72 by 80 inches and is great for taller people. Whichever you prefer, Mattress Firm now offers a huge selection of memory foam mattresses available in RV sizes.

What is a Split-King Mattress?

A split-king mattress is made up of two twin xl mattresses placed side-by-side measuring a total of 76" by 80". This helps deliver a more personalized feel for couples who have different bed type preferences and sleeping positions. To order or learn more, please contact our Sleep Experts® by call or chat.
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