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The Complete Guide to Mattress Sizes & Dimensions

Perhaps the most important part of purchasing a new mattress is finding the perfect size based on your specific needs. Are you a single sleeper or a couple? What is your room size? What is your budget?


A new bed that matches your personal preference is a joy to bring home. To assist you in your search for the right mattress, here is a mattress size chart with all of the popular mattress sizes available as well as the mattress dimensions.

Standard Mattress Sizes and Dimensions

Twin Mattress

38” wide x 75” long

The standard mattress size for a Helix Twin mattress is 38 inches wide and 75 inches long. A Twin bed size is ideal for smaller rooms and single sleepers with limited space.

Twin XL Mattress

38” wide x 80” long

A Twin XL mattress is 5 inches longer than a twin size bed. This Twin XL mattress measures 38 inches wide and 80 inches long. Oftentimes, a Twin XL bed is used in student college dorm rooms and guest rooms. Taller individuals may prefer a Twin XL size over a standard Twin size.

Full Mattress

Full size mattress dimensions - 54

54” wide x 75” long

A Full size mattress can be a great choice for both single adults sleeping alone and couples sharing a bed. A Full mattress measures 54 inches wide and 75 inches in length. It's a good fit for tall people and individuals looking for extra sleeping space, which is why a full bed is one of the most common sizes people shop for.

Queen Mattress

Queen size mattress dimensions - 60

60” wide x 80” long

Because of its expanded dimensions at 60 inches wide and 80 inches long, a Queen bed size is often considered an upgrade from a Full size bed. A Queen size mattress is ideal for couples and individuals looking for extra space in the bed if a Full size mattress isn't quite roomy enough. If you plan to share your bed, a Queen size bed may be the best mattress size for you.

King Mattress

King Size mattress dimensions - 76

76” wide x 80” long

A King size mattress is a significantly larger mattress that measures 16 inches (one and a half feet) wider than a Queen size mattress. For those with enough space to spare, King size beds are a common size for a master bedrooms, measuring 76 inches wide and 80 inches long.


A King bed is perfect for couples, families with kids or pets (who are allowed to snuggle in bed), or simply anyone looking for extra length, width, and leg room in their mattress.


California King Mattress

CA King size mattress dimensions - 72

72” wide x 84” long

What's the difference between a King mattress and a California King mattress?California King size bed is four inches longer than a Standard King size bed but four inches narrower, meaning these two mattress sizes don't share the same bed frame dimensions, as the California King will provide more leg room but fewer inches of space across the width of the bed for couples.


The standard size of a California King bed measures 72 inches wide and 84 inches long. Keep in mind, if you're choosing either a California King size bed or a King mattress, be sure to accurately measure the dimensions of your bedroom, as you will need adequate room size to fit these larger mattress sizes.


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Mattress & Bed Size FAQs

What’s the difference between a standard King and a California King?

It’s simple: the size. Standard Kings measure 76 inches wide and 80 inches long. California King beds measure 72 inches wide by 84 inches long. Cal King mattresses are 4 inches narrower and 4 inches longer than standard King mattresses. You typically can't interchangeably use the same bed frame or sheets for both bed sizes.


Do two Twin size mattresses equal one Full size mattress?

No. Twin beds measure 38” by 75”. Combining two would be significantly wider than a standard Full. Two Twin size mattresses are the width of a king mattress, though still 5 inches shorter. Two Twin XL mattresses, however, would be the same length and width as a King size mattress.


Is a Full size mattress the same thing as a “Double” mattress?

Yes. The terms Full bed and Double bed are used interchangeably to describe mattresses that measure 54 inches wide and 75 inches long.


What mattress should I get for a small bedroom? What about a small apartment or studio apartment?

It really depends on the size of your sleeping space and personal preferences. If you’re a single adult, a Full bed would be a space saver compared to a Queen bed and could be sufficient. However, for couples, a Queen bed is often recommended. Single sleepers who prefer having more floor space over sleeping space may want to consider a Twin mattress (or, for tall people, a Twin XL mattress) though for many they may not provide enough width.


What mattress size should I get for a guest bedroom?

Again, it depends on the space and your needs. Full size beds are commonly used in guest rooms as they take up little space and can accommodate two sleepers in a pinch. If you have the space though, we’d recommend going for a larger mattress, like a Queen size bed, for your guest room.


Do mattress lengths and widths have anything to do with thickness?

Length and width are not typically indicators of how thick a mattress will be. Mattress thickness is usually determined by the materials used to make the mattress, and whether it is a pillow top mattress, as the plush top will generally give it a taller profile by a couple of inches. Different mattress constructions can sometimes differ in height - for example, solid memory foam mattresses sometimes aren't as tall as innerspring mattresses.