Want CNET to notify you of price drops and the latest stories?

Mattress Size: Why It Matters and What to Know When Deciding

The size of your mattress is more than just the dimensions. Here's everything you need to know.

McKenzie Dillon Writer
McKenzie, a Certified Sleep Science Coach and proclaimed mattress expert, has been writing sleep content in the wellness space for over four years. After earning her certification from the Spencer Institute and dedicating hundreds of hours to sleep research, she has extensive knowledge on the topic and how to improve your quality of rest. Having more experience with lying on mattresses than most, McKenzie has reviewed over 150 beds and a variety of different sleep products including pillows, mattress toppers and sheets. McKenzie has also been a guest on multiple radio shows including WGN Chicago as a sleep expert and contributed sleep advice to over 50 different websites.
Expertise Certified Sleep Science Coach, Certified Stress Management Coach, Bachelor of English.
McKenzie Dillon
5 min read
Tharon Green/CNET

There are a lot of factors to consider when you're shopping for a mattress -- the firmness, the material and the feel. Mattress size is another important factor many people forget about, but it's actually one of the most important factors. It's more than just the dimensions of the mattress, size helps determine how much you will spend on your mattress

CNET Sleep Tips logo

You have your pick between a range of mattress sizes, from single-person twin-sized bed for when your kid graduates from a crib to an extra-wide California king fit for couples who like to sprawl. What mattress size you choose will depend on your height, weight and preferences. In this mattress sizing guide, we explore the dimensions of each bed size, from the most common to custom-made options. 


38 by 75 inches (96.5 by 190.5 centimeters)

Tharon Green/CNET

A twin size is best for children, or single sleepers who want to maximize the space in their room. Because they take up very little space, they can fit in room sizes as small as 7 by 9 feet. Twin-size mattresses are popular for kids because it's the least expensive size you can buy, and the bed won't take up as much space in their bedroom, leaving them room to play.

Check out CNET's picks for the best twin mattresses.

Twin XL

38 by 80 inches (96.5 by 203 cm)

Tharon Green/CNET

Twin XL is a long twin mattress and is best for taller children, young adults in college, or single-sleeping adults who need the extra leg-room. An 8- by 10-foot room is the smallest you should go to fit a twin XL mattress comfortably. It's also common for brands to have two twin XL mattresses as a split king. Keep in mind that it's harder to find bedding to fit a twin XL mattress because the size is most commonly used in college dorms. That means you can usually find plenty of twin XL bedding during back to school season. Outside of that, you might be limited in what you can buy.


53 by 75 inches (134.5 by 190.5 cm)

Tharon Green/CNET

Because full size mattresses are bigger than a twin, but cheaper than a queen, they're popular for young adults, or couples who don't mind cuddling to maximize the space in their bedroom. The recommended room size for a full size mattress is at least 10 by 10 feet. 

Check out CNET's picks for the best full size mattresses.

Full XL

54 by 80 inches (137 by 203.5 cm)

A good compromise between a full and a queen size is a full XL. It offers the same width as a full mattress but is just as long as a queen. Single-sleeping adults who need the extra leg and or pet space typically would be well-off on a full XL bed. Keep in mind, though, it will be a little harder to find bedding for a full XL mattress than a full or queen. 


60 by 80 inches (152.5 by 203 cm)

Tharon Green/CNET

Queen size mattresses are best for single sleepers who enjoy their space. They're also good for couples, just as long as nobody is over 6 foot, 5 inches. It's currently the most popular mattress size in North America. The recommended room size for a queen size mattress is at least 10 by 11 feet. 

Check out CNET's picks for the best queen mattresses.


76 by 80 inches (193 by 203 cm)

Tharon Green/CNET

A common choice for couples with kids or single-sleepers who like extra space to spread out, the recommended room size for a king bed is at least 12 by 12 feet. A larger size bed comes at a higher cost, both for the mattress and the bedding, so keep that in mind if you are on a budget.

Check out CNET's picks for the best king size mattresses.

California king 

72 by 84 inches (183 by 213 cm)

Tharon Green/CNET

A California king is longer than a standard king, but not quite as wide. It's best for tall single-sleepers or couples who have pets who sleep on the bottom of your mattress. 

Custom sizes

Maybe the mattress sizes listed above don't suit what you're looking for. Instead, you want something that fits between that one random nook in your bedroom, or an extra-oversized mattress so your big family can join together for movie nights. Whatever the case may be, Healthline has a great list of the best custom mattress brands you can order from. 

Mattress size FAQs

Which bed size is best for a couple? 


While two people can fit in a full size bed, you'll be more comfortable sharing a queen or king.

Getty Images

It depends on the space you have in your bedroom, and how much space you or your significant other require. For maximum space in your bedroom, a queen is perfectly suitable. Maybe even a full if you're down to cuddle. For large master bedrooms, king or CA king beds would be ideal. 

What's the most popular mattress size?

As of right now, the most popular mattress size is a queen which measures 60 by 80 inches. It offers ample space for single sleepers and couples, and is more affordable than a king. 

What size is a king mattress?

The dimensions of a king mattress are 76 by 80 inches (193 by 203 cm).

What size is a twin mattress? 

A twin size mattress is the smallest standard size, and measures around 38 by 75 inches (96.5 by 190.5 centimeters).


Twin size beds are most commonly used for kids.

Getty Images

What size is a California king mattress?

A California king bed is the longest standard mattress size. Its dimensions are 72 by 84 inches (183 by 213 cm). 

What is a split king mattress?

Split king beds are popular among couples with adjustable bed frames who want independent control of their side, or couples who just want their own individual bed space. 

How big is a crib mattress? 

North America has specific crib requirements for maximum baby safety. Those requirements state that a crib should be between 51.6 to 53 inches long, and 27.25 to 28 inches wide. 

How do I buy an RV mattress?

You'll want to measure the space you have for a mattress in your RV. Sizes range from RV bunk, RV full, RV queen to RV short queen, RV king and RV CA king. Luckily, there are a lot of sizes to choose from and you can likely find a comfy fit. 

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.