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The Complete Guide to Mattress Sizes and Dimensions

Should you buy a King or California King sized bed? Is a Full sized bed large enough for two people? What’s the deal with Twin XL? The most important factors to consider when buying a mattress are often your room size, whether or not you're sharing a bed every night, and your sleeping position

Overall, it's these personal preferences that determine what mattress will best suit your lifestyle and budget. Whether you’re in the market for a new mattress or planning the layout of a bedroom it’s important to know definitively how to think about mattress sizes.

A Quick Mattress Size Guide of Standard Sizes


Twin Size Mattress 39” wide x 75” long
Twin XL Size Mattress 39” wide x 80” long
Full Size Mattress 54” wide x 75” long
Queen Size Mattress 60” wide x 80” long
King Size Mattress 76” wide x 80” long
CA King Size Mattress 72” wide x 84” long


Standard Mattress Size Chart


Standard Mattress Dimensions 

Now we'll go through the standard mattress sizes and give some insight so you can decide how your new mattress will fit into your room or if you'll have extra space.


King vs. California King Size Mattresses

One of the most common pieces of misinformation we hear about mattress sizes relates to the length and width of King vs. California King. A standard King size mattress is WIDER and SHORTER than a California King mattress. This of course means that a California King mattress is LESS WIDE, but LONGER than a normal King size bed. 

We frequently hear this comparison wrongly swapped, but now you know!

If you’re deciding  what size works best for you, we advise thinking through the shape and design of your bedroom. Both beds should give ample width and length for two people of various shapes and sizes. 

The one caveat is if one partner is a taller individual, he or she may be more comfortable with the extra length of a California King, though it's not necessarily a larger mattress.


Queen Size Mattress

Queen beds are among the most common standard mattress sizes, measuring 60 inches wide and 80 inches long. As one of the most popular mattress sizes on the market, queen size beds are generally designed for couples, especially those who live in smaller apartments in urban areas where renters need to get as much living space as they can out of their master bedrooms. 


Full Size Mattress

Another question we get a lot is whether or not two people can comfortably share a Full size mattress, also known as a "double bed." 

You’ll notice that a Full mattress is half a foot thinner and five inches shorter than a Queen size, which is your standard option for couples living in smaller bedrooms. 

That reduction in both length and width can make a major difference or it could be barely noticeable – it really depends on your size and sleeping position. If one partner moves at night, space permitting, we would suggest using a Queen mattress or larger. However, for single adults, a full size bed generally provides enough space to stretch out.


Twin Mattresses vs. Twin XL Mattresses

Let us take you back to your college years…because that’s basically a college dorm room is like the only place you’ll really find Twin XL size mattresses outside of certain bunk bed units and special situations like maybe a guest room. 

The “XL” refers to the mattresses length, which is 5 inches longer than your normal twin size mattress, giving college students more leg room than those who have a standard twin size bed. 

Twin beds, on the other hand, are among the smallest mattress sizes on the market. These are often the best mattresses for single sleepers looking to economize on space as well as children under the age of 18 because of their length and width.


Buying a Mattress That Fits You Perfectly

Helix Sleep doesn't just feature customizable mattresses, We take an intuitive approach to matching you with your perfect mattress. With our signature sleep quiz, we can guide you to the mattress of your dreams.