Twin vs. Full Size Mattresses: What’s the Difference?

We all like a little extra space when we sleep, but sometimes, there just isn’t enough room for a King- or Queen-size mattress. If you’re looking for a new mattress for your growing teen, a college dorm room, or simply trying to maximize space in your new apartment, a smaller size bed might be your best option. 

With so many mattress sizes to choose from, we’ve created a simple mattress size guide to help you understand the mattress dimensions so you can choose between a standard Twin and Full size bed. 

The Difference Between Twin and Full Mattresses

Standard Twin and Full beds are both great space savers compared to King- and Queen-size mattresses. Both are less wide than a King and Queen and are the mattresses of choice for single sleepers. 

If you’re considering investing in a smaller bed, the first thing to know is that Twin and Full mattresses are not actually the same size. Twin beds are a few less inches than Full-size beds, and are most commonly found in children’s bedrooms and dorm rooms. Full-size beds are slightly longer than Twin-size beds, and are generally seen as the best option for taller teens and adults. 

Twin-Size Beds

Commonly referred to as single beds, Twin-size beds are the standard mattress option for children after they have grown out of their cradle or crib mattress. Not only are Twin-size beds a great option for growing kids, but they can also function as space savers, making them the perfect choice for bunk beds in vacation homes or for small guest rooms and lofted spaces. Sometimes, smaller sizes are the better option!

Twin-Size Mattress = 38 x 75 inches

Twin Mattress

Full-Size Beds 

Full-size mattresses are often called Full beds or Double beds, but contrary to their name, they are best for single sleepers. That said, some couples (especially those living in smaller spaces) find Full-size beds to be a cozy and comfortable option. Full-size beds are also a great choice for single adults and growing children who may need extra leg room in the future. 

Full-Size Mattress = 54 x 75 inches 

The Third Option

To make things a little more confusing, there is another single-size bed called the Twin XL that is a different size from both standard Twin and Full mattresses. Twin XL beds are significantly longer than Twin-size mattresses and a little wider too. As a result, Twin XL mattresses are a great option for adults who have a small bedroom but still require the length of a Queen-size mattress. 

Twin XL Mattress = 39 x 80 inches 

Mattress Considerations

Consider Your Space

The first thing to consider when choosing your perfect mattress size is the layout, room size, and measurements of your bedroom, studio, or vacation home. As important as sleep is, a mattress that is too large can suffocate the space in your bedroom, leaving you without the room you need to move around and, more importantly, relax. 

Think of the Sleeper

If you’re purchasing a new bed for your child, it might be wise to invest in a bigger sleep setup that they can grow into. Similarly, if you are choosing a bed that a couple might sleep in (like a guest bed, for example), it’s usually better to opt for a wide mattress, such as a Full or a Queen


Even if you have space for a Full bed you might want to consider a Twin- or a Twin XL-size mattress for its price point. Not only are standard Twin mattresses more affordable than double beds, they also leave you the extra space you need to move around in the bedroom. 


Kid's Room Twin Mattress

The Breakdown

Now that you have all the information you need to choose between a standard Twin-size mattress, a Twin XL, and a Full mattress, we are going to break down the differences between the three sizes to make your decision a little easier. Here we go…

Choose a Standard Twin-Size Mattress if:

  • You’re shopping for your child’s first “big kid bed”
  • You have a bunk bed setup in your kid’s bedroom or vacation home
  • You have a small sleeping area and you don’t need a ton of leg room
  • You want a more affordable option than a Twin XL or Full mattress

Choose a Twin XL if:

  • You don't have a ton of space in your bedroom but you *need* that extra legroom
  • You need more space for your kid to grow into the mattress but you’re not quite ready to invest in a Double or a Full
  • You want to set up your teen with a fresh mattress for their dorm room
  • You’re a couple who wants to sleep separately but you still want the same amount of legroom as you had with a Queen-size mattress
  • You want a more affordable option than a Full mattress

Choose a Full Mattress if:

  • You want to opt for a mattress with more inches that your teen can grow into
  • You don’t have enough space for a King- or Queen-size mattress but you like a little extra width on your sleep setup
  • There’s going to be two people sharing a bed but you don’t have the space for a larger mattress
  • You want a more affordable option than a King or a Queen-size mattress

Bed Size is Just the First Step of the Journey

Once you figure out your perfect mattress size, the fun begins. Not only do you get to choose the perfect mattress for your sleeping type, but you also get to shop for sheets, a comforter, and a sturdy bed frame or box spring to support your mattress. Happy hunting!

If you’re looking for mattresses for an adjustable bed frame, or two different style mattresses to create a perfect King-size bed, we’ve got your guide here.

Curious about the bigger beds to fill out your master bedroom? Learn all about the history of custom beds and the celebrity favorite California King mattress here

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T&N Team
T&N Team

Tuft & Needle, a Phoenix-based mattress company, is leading the revolution against mattress markups, poor customer service, and inferior products by creating exceptional, honestly priced products, and redefining the purchasing experience.

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