Mattress Sizes and Dimensions: Which Bed Size Is Right For You?

Beyond personal preference, there are a number of factors to consider before picking a mattress size. You’ll want to think about the size of your bedroom, who you’ll be sharing your bed with, and available space.

In this guide, we illustrate the dimensions of all six standard mattress sizes to help you choose the best one for your needs. We also answer some commonly asked questions when it comes to bed sizes and choosing a mattress.



Twin bed dimensions: 38” x 75”

twin mattress is the smallest bed on the market at 38 inches wide and 75 inches long. Its compact footprint makes it ideal for single sleepers — either children or adults with small spaces like a studio apartment.

Best for: kids, bunk beds or single sleepers.

Room size: The minimum room size for a twin bed to fit naturally is 7 x 9 feet. An 8 x 10 square foot room may be required for the bed to fit with other furniture, such as a desk or dresser.


Twin XL

Twin XL bed dimensions: 38” x 80”

The twin’s slightly longer cousin, the twin XL mattress, is the most popular size for college dorm rooms. It measures five inches longer than a twin, at 38 inches wide and 80 inches long. In addition to students, a twin XL mattress is a good solution for taller teenagers and individual adults with limited space. These beds can also be put together if you’re choosing a split king adjustable base for full body adjustability!

Best for: taller teenagers, single adults or anyone with limited space.

Room size: The minimum room size for a twin XL bed to fit naturally is 8 x 10 feet. Twin XL beds can also work well in narrow rooms that are at least 7 feet wide.



Full size bed dimensions: 53” x 75”

The full mattress is a good starter mattress for young adults or recent grads living on their own for the first time. Sometimes called a double, the full is 16 inches wider than a twin at 53 inches wide and 75 inches long. A full is not recommended for couples who like to share the bed with pets or their children, but it’s a smart choice for guest rooms.

Best for: young adults, couples who like to cuddle or guest rooms.

Room size: The minimum room size for a full bed to fit comfortably is 10 x 11 feet.



Queen size mattress dimensions: 60” x 80”

The most popular mattress size on the market is the queen mattress, which is traditionally used in a master bedroom. At 60 inches wide and 80 inches long, the queen offers plenty of space for couples or individuals who like having extra room to move around in bed.

Best for: couples or adults who like to sprawl out.

Room size: The queen mattress fits best in a master bedroom that is at least 10 x 10 feet.



King size bed dimensions: 76” x 80”

At 76 inches wide and 80 inches long, the king mattress is large enough to accommodate couples who share the bed with their children or a sizable pet (think: a Great Dane). A king bed can be made of two twin beds pushed together, which is referred to as a split king. King beds are large enough that both sleepers can sprawl out with room to spare.

Best for: couples who enjoy their space or share a bed with children.

Room size: A king mattress fits best in a spacious master bedroom, preferably at least 12 x 12 feet.


California King

California king bed dimensions: 72” x 84”

The longest mattress on the market, the California king mattress is a whopping 72 inches wide and 84 inches long. Its generous length makes it ideal for taller individuals, especially people more than six feet tall. Of course, people of average height might also benefit from a California king depending on how many people and pets are sharing the bed

Best for: couples with kids or pets who want a luxurious amount of space.

Room size: A California king mattress fits best in a large master bedroom of at least 12 x 12 feet.


Which Bed Size Is The Best For Me?

If it’s time for a new mattress, you may be wondering which size is right for you. There are many things to consider, like who will be sleeping in the bed, how much space you will need, how much room is in your bedroom, and any specific health or sleep issues you might face.

Buying a new mattress is not a one-size-fits-all situation, so it’s essential to evaluate your individual needs. If you have a history of back pain or sleep problems, you may want a free trial period to help you make sure you’re comfortable with your new mattress.

Here are some other major factors you will want to consider when choosing a mattress.


Who Will Sleep In the Bed

Will you be sharing the bed with a partner? Do your children or dogs typically sleep with you? These are questions to ask yourself before deciding on mattress size. Typically twin, twin XL, and full mattresses are meant for one person. The queen, king, and California king beds are big enough for two sleepers.

If you are going to sleep with another person, consider how close you like to sleep and your usual sleeping positions. If you both like to stretch out when sleeping, the extra room afforded by a king or California king will be appreciated.

Your Room Size

The amount of space available to you should also be considered. A larger mattress will take up more space in your bedroom, so you will need to plan accordingly.

Here are the mattress sizes in square inches and square feet. Ensure there is plenty of space for the mattress in your room.


  • Twin: 2,925 sq. in./20.3 sq. ft.
  • Twin XL: 3,120 sq. in./21.7 sq. ft.
  • Full: 4,050 sq. in./28.1 sq. ft.
  • Queen: 4,800 sq. in./33.3 sq. ft.
  • King: 6,080 sq. in./42.2 sq. ft.
  • California King: 6,048 sq. in./42 sq. ft.

Your Body Size

You should take your height and width into consideration when choosing a mattress. A typical twin mattress is 75 inches long, while a twin XL is 80 inches long. If an individual is taller than six feet two inches, a twin mattress is probably not for them. Instead, it’s best to go with the XL, full, queen, or king bed, all of which can accommodate someone who is up to 6 feet 7 inches.

Those that are taller than 7 feet should opt for a California king bed. For those who want more space on either side of their body, a full, queen, or king bed will be the most comfortable.

Your Budget

The amount of money you are willing to spend on a mattress can also help you choose the right size. A king will cost more than a queen, and a queen more than a full, etc. Buying a mattress that meets both your size needs and your financial needs is key.

Frequently Asked Questions

Assessing your options when it comes to choosing a mattress can be confusing, especially for those who don’t know the lingo. To help you with your search, here are some questions we hear frequently from our customers.

Mattress Dimensions FAQs

A single mattress and a twin mattress are one and the same — both have the dimensions of 38 inches by 75 inches. These, along with the twin XL (which is a little longer), are designed to fit one person.


The term “twin” came about because these mattresses were often placed two to a room, either in children’s rooms, hotels, or other rooms that are meant to be shared by more than one person.

A twin, also known as a single mattress, is the smallest size available on the market today. Casper twin mattresses are 38 inches by 75 inches and are the perfect size for a child or short single sleeper. Single sleepers that need a longer bed can try a twin XL, which is 80 inches long.

Although a twin XL is 15 inches narrower than a full, it’s 5 inches longer. Twin XL beds usually can’t comfortably accommodate more than one person, but they are an ideal choice for a single sleeper that’s too tall for a traditional size bed. Twin XL beds are great for small, narrow bedrooms where there’s not a lot of floor space, and are often the bed of choice for college dorm rooms and apartments.

The dimensions for a Casper double size mattress and a full mattress are 53 inches by 75 inches. In this case, both names represent the same kind of mattress. This bed is on the smaller side, but still able to fit two people if needed.

The full-sized bed (also known as a double) can fit two people. In fact, full mattresses were the most common size used by couples in the 1960s. They are advantageous because they are able to fit into smaller rooms. However, many adults these days prefer a larger bed.


The full bed is 53 inches by 75 inches, leaving only 26.5 inches across for each person’s personal sleeping area. The slightly larger queen bed offers 30 inches of space per person, while a king offers 38 inches per person. Depending on you and your bed mate’s sizes and sleeping styles, you may consider a queen or a king rather than a full.

Full vs. queen size beds are some of the most common choices for adult bedrooms. While a full measures 53 inches by 75 inches, a queen measures 60 inches by 80 inches. Full beds are good for young adults, couples who cuddle in their sleep, and guest rooms, while queen beds are an ideal bed for people who like to sprawl out at night.

If you’re deciding between a king or California king, it all comes down to four inches. A king mattress is actually four inches wider than a California king, while a California king is four inches longer than a king at 72 inches by 84 inches.

The king-sized bed is the widest bed that Casper sells, measuring at 76 inches by 80 inches. Those looking for a longer bed can purchase the California king, which is slightly longer and narrower, measuring 72 inches by 84 inches. Both beds should be large enough to fit two adults, although those who are taller may prefer a California king.

To determine the dimensions of a mattress, measure it from head to foot for the length and from side to side for the width. It may be helpful to measure the depth of the mattress as well, from the bottom where it rests on the box spring to the top.

You will want to use a tape measure and record these three dimensions, in inches, and repeat if necessary if you use a foundation. It’s important to measure your mattress and box spring before buying an encasement or bed.

Now that you know all about the sizes and dimensions of different beds, you should be able to make an informed decision regarding your next mattress. Once you have your sizing figured out, consider an adjustable bed frame for the ultimate comfort or some soft, breathable bedding to outfit your new investment!