King vs Twin XL Beds – Mattress Sizes

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Fun fact: assemble two Twin XL mattresses next to one another and they have the identical dimensions of a King bed. The Twin XL is the same width as the Standard Twin, but the mattresses 5″ of additional length make it the length as a King. Read on for our complete comparison of Twin XL vs King mattress sizes.

The Basics

Standard (or Eastern) King:

Standard King
Width Per Person38"

Who is this bed size ideal for?

A King bed is typically best suited for couples. In fact, a King mattress is the equivalent of each individual sleeping in their own Twin XL bed (pushed together). The King bed offers each sleeper 8 additional inches of space compared to a Queen sized bed, which makes it ideal for Master Bedrooms, but potentially too large for some individuals.

Twin XL

Twin XL

Who is this bed size ideal for?

The Twin XL has the identical width as a Standard Twin, but it’s approximately 5″ longer, making it the same length as a Queen or King. The Twin XL is a solid option for college dormitories or taller children who may have smaller rooms. Travelers will also see them in hostels where multiple beds are in one large room.

Related: Mattress Sizes

Other Size Options


The California (Western) King is decently popular because it’s narrower and longer than a traditional King size mattress, which can sometimes be a little too wide for a medium-sized bedroom.

CA King

The Split King is similar to a Standard King, but it’s 2” wider and split down the middle, allowing each individual sleeper to have their own designated section of the bed.

Split King
Width39" (each half)


A Standard Twin is also known as a Single bed, and Twin mattresses and beds are often the next steps for children who have outgrown their cribs. Twin mattresses are also a great option for guest rooms or smaller bedrooms, as well as bunk beds, which are traditionally manufactured in Twin size.


What Size Is Best?

Who will like the King mattress?

  • People upgrading their Master BedroomKing sized beds tend to be the best fit for larger master bedrooms, where there is ample space not only for the new bed but for the additional pieces of furniture and accessories in the bedroom.
  • Individuals who like to stretch out, while it comes down to personal preference, many couples opt for a King size bed over a Queen (or a Full for that matter). In a King-sized mattress, each person gets 38″ of space on each side, which makes it comfortable for couples to spread out, or for the youngest family member to hop in during the night.
  • Shoppers with a budget as massive as a King bed. Everything adds up when shopping for a new mattress. People who move from a Queen – or something smaller – to a new King bed, will probably need to purchase a sturdy, reliable bed and bed frame, as well as some comfortable King-sized sheets, and potentially some more pillows.

King sized bedTuck mattress (King) – check out our review, here. 

Who Will Like the Twin XL?

  • A young adult or child will be well-suited for a Twin XL mattress. As mentioned earlier, Twin-sized beds are essentially the next step up from a crib mattress. A Twin XL’s dimensions are 38″ x 80″ and could be a good fit for a child’s room, or even a teenager who could use the additional length.
  • People trying to save money might have room for a Full/Double bed but can’t afford the frame, mattress, and sheets. Shoppers who need a new mattress can consider a Twin XL. The bed will definitely be more affordable since it’s a smaller mattress. Saving on space also gives sleepers an extra 5″ in length, and many Back-To-School sales offer bedding bundles in Twin XL size.
  • For people who need a bed for a smaller room, one Twin XL bed will look very small in a Master Bedroom (unless it’s a smaller bedroom). Instead, the the Twin XL is probably a good fit as a replacement for a crib in a nursery or a smaller room that maybe two people share – like a kid’s room.

Twin size bunk bedsKoksharov Dmitry/Shutterstock

Things To Consider

Here are some tips and things to think about before making a purchase.

  • Measure the space and leave room for movement. Shoppers who are thinking about making the jump from a crib to a Twin XL – or are ready to live large and get a King bed – make sure it fits it in your bedroom. Just know that it’s easy to get caught up in an impulsive shopping moment and end up with a bed that doesn’t exactly fit. An article from Th!ngz Contemporary Living says that most designers will recommend 30″ of space around your bed for movement. That means that a King size will be best for a large Master bedroom.
  • Consider how you’ll get your bed into the room. While Twin XL beds and mattresses won’t be too difficult to get through doorways or upstairs,  a King mattress may take some maneuvering (and another set of hands) to get into a bedroom.
  • Shop seasonally whenever possible. There are specific times during the year that mattresses and beds will go on sale. For shoppers who are on a budget but want to upgrade to a bigger bed, it might be worth waiting to make a purchase during that time. Back-To-School is an excellent time to shop for Twin XL beds as they’re very common in college dorm rooms. For mattresses, Labor Day weekend is often a good time for sales.


There are a variety of reasons to go with either a Twin XL bed or a King bed. It’ll depend on sleep needs, room size and – of course – budget! One hack that might be worth investigating is seeing if the cost of two Twin XL beds is cheaper than a King bed. Sleepers can put two Twin XL mattresses on a King frame for a Split King mattress (always check dimensions first as some brands may change theirs).

Katie Golde

Katie previously managed the day to day operations of the Mattress Clarity news site and reviews sleep products in addition to writing and editing sleep news. She hails from Austin, where she lives with her growing family. She is a Certified Sleep Science Coach and has a master’s degree in Journalism from Northwestern University and has a background in health and science content. Her work can be found in print and online publications like Discover Magazine, USA Today and The Huffington Post.