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Twin vs Full Mattress Sizes: What’s the Difference?

The main difference between a twin bed and a full bed is their width. At 75 inches long, twin and full-size mattresses are the same length. But the 38-inch-wide twin is much narrower than the 54-inch full.

Depending on certain factors, those under six feet tall or sleeping alone could do well on a full or a twin bed. However, things can get more complicated for those who are taller or sleeping with a partner.

What Is a Twin-Size Mattress?

The standard twin or single bed is the smallest of the standard sizes because it measures only 38 inches wide and 75 inches long. The twin mattress’s small size makes it perfect for growing kids and single adults who need a bed for a compact space. ·

The twin-size mattress is perfect for bunk beds, dorm room bed frames, studio apartments, and other small spaces. Keep in mind twin mattresses are too large to serve as crib mattresses. Twin beds are best suited for average-height adults. 


  • Easy to move
  • More budget-friendly
  • Fits in compact spaces


  • Only for single sleepers
  • Not suitable for taller adults
  • More ideal for smaller rooms

Suitable For:

  • Single sleepers
  • Older children
  • Those with small spaces

MLILY’s Twin Mattress

One of our favorite twin mattresses on the current market is the MLILY ONYX Plus Hybrid Medium. This mattress offers cooling comfort and contoured support for an incredible sleep experience in a compact package.

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The ONYX Plus starts with a cooling cover infused with graphene. This thermally conductive material draws heat away from your body and helps create a hostile environment for bacteria, mold, and other microbes. 

The copper gel-infused memory foam comfort layer works with the graphene-infused cover to pull body heat even further away from you, keeping the sleep surface cool as a cucumber. The AeroFusionTM technology in the foam also keeps air flowing for even more cooling power and moisture regulation. 

The ONYX Plus gets its buoyancy from a transition layer of flex comfort foam. This transition foam offers durable support on the sleep surface, even as the comfort foam above relieves pressure and contours to your body. 

Bringing up the bottom of the mattress, a support layer of pocketed coils offers adaptable and dynamic support that will move with you and bounce back into place. These coils rest on top of a layer of ultra-firm base foam to increase the durability and stability of the mattress.

Mattress Highlights:

  • Graphene and copper keep your mattress cool and free from microbes.
  • Pocketed coils offer responsive and adaptable support.
  • The medium feel is versatile for many different sleepers.
  • Hot sleepers
  • Combination sleepers
  • Sleepers with allergies

What Is a Full-Size Mattress?

The standard full-size mattress is also known as a double bed because it is technically the smallest of the standard sizes that two adults can use. Since the entire bed is 54 inches wide and 75 inches long, most couples are usually more comfortable on a queen or king. 

Full-size beds are best for adults who want extra room to spread out while maintaining a more compact size. Full beds will fit into all but the smallest bedrooms, so they’re great for apartments and older houses, which usually have smaller rooms; though, like with the twin mattress, full mattresses are generally not the best for individuals over six feet tall.


  • Perfect for single adults who want more room
  • Still compact enough for smaller bedrooms
  • Easier on the budget than larger sizes 


  • Not for taller individuals
  • Couples may need more room for optimal comfort
  • Ideal for bedrooms with sufficient space

Suitable For:

  • Singles who want more room 
  • Some couples
  • Those with smaller bedrooms or budgets

MLILY’s Full Mattress

If you’re looking for an amazing full-size mattress, check out the MLILY ONYX Max Hybrid Plush. This soft and luxurious mattress offers tons of cooling technology to ensure it doesn’t overheat, even when it hugs your body. 

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The ONYX Max features a graphene-infused knit cover that packs a one-two punch of cooling power. The graphene conducts heat away from your body, while the knit weave keeps cool air flowing. 

The cover works with the aerodynamic copper gel-infused memory foam to ensure the sleep surface does not build up heat because it conducts your body heat down away from you and breathes in cool air all night.

Under these cooling layers, a layer of AdaptiFoamTM absorbs pressure to provide a weightless sleep experience – perfect for side and petite sleepers. A liquid gel flex-foam layer sits underneath the AdaptiFoamTM to sandwich it between cooling technologies. 

All this foamy comfort sits atop a pocketed coil support layer that provides dynamic, contoured support that bounces back as soon as you move to minimize body impressions and speed up response time. 

Mattress Highlights:

  • The plush feel offers tons of pressure relief for those who need it.
  • Cooling technologies ensure this soft mattress does not overheat. 
  • The pocketed coil response layer is bouncy and adaptable. 
  • Hot sleepers
  • Side sleepers
  • Lighter-weight sleepers

MLILY Firm Alternative

Stomach and heavier sleepers may find the ONYX Plus and ONYX Max too soft. If this is the case, check out the ONYX Hybrid Firm

This firm hybrid mattress offers all the cooling comfort of the Plus and Max with the added perk of more support. It’s also more budget-friendly for those looking to keep the costs of their new mattress down. 

Other Factors to Consider When Choosing Between Twin vs. Full Bed Sizes

If you’re done choosing the right mattress size, you’ll also need to consider a few other factors when selecting a mattress to fit your needs. 

Firmness Level 

The mattress’s firmness is one of the most significant factors in providing optimal comfort for each individual. Most people should select a mattress based on their sleep style, size, and weight. Generally speaking, the following sleep positions correspond to the following firmness levels:

  • Side sleepers need medium-soft mattresses.
  • Combination sleepers need medium mattresses.      
  • Back sleepers need medium-firm mattresses.
  • Stomach sleepers need firm mattresses.

Your body weight can also impact your firmness needs. Heavier sleepers generally need firmer mattresses, while lighter sleepers need softer ones. 

If you’re purchasing a mattress for two, you will also need to consider the firmness needs of both partners. Individuals with different firmness preferences or those who tend to move around a lot during sleep may also benefit from a split king. The split king is the size of a standard king, but it uses two twin XL mattresses on each side of the bed to be customized to meet the individual’s specific needs, resulting in a more comfortable and restful sleep experience for both partners.

Mattress Type

There are four basic mattress types:

  1. Memory Foam

Made entirely of flexible polyurethane foam. Generally highly contouring and supportive, but less buoyant and responsive. 

  1. Latex Foam:

Made entirely of natural rubber foam. Generally very bouncy and buoyant, but less flexible than memory foam. 

  1. Innerspring Mattress

Made with a support layer of open coils and a comfort layer of plush materials, including foam, cotton, wool, etc. Usually responsive but not very contouring or pressure-relieving.

  1. Hybrid Mattress:

Made using comfort foam on top and pocketed coils underneath. Combines the flexibility and pressure relief of a foam mattress with the responsiveness of coils. 

Each type of mattress offers responsiveness, pressure relief, and contouring levels; therefore, you may need a mattress comparison to decide which is right for you.


You’ll also have to think about other components of your bed. You’ll need a bed frame, potentially box springs or a mattress foundation, and a sheet set. 

For an individual to opt for a full mattress, remember that you’ll need to budget more, not just for the bed itself but for all the accessories that come with the mattress. This may factor into your decision to get a twin or full mattress.

Standard Mattress Size Comparison

Looking to explore something other than a twin or full mattress? There are plenty of different options to consider as well.

Twin XL and Full XL   

twin-xl mattress

If you’re on the taller side but want to stick with the twin or full width, a twin XL mattress or full XL mattress may be for you. These mattress sizes have the same width as the standard twin and standard full beds, respectively, but they add five inches to their length. This means the twin XL bed is 38 by 80 inches, and the full XL bed is 54 by 80 inches. 

Remember that the full XL is more on the unconventional mattress size run, so finding a full XL may be more challenging than a twin XL. But there are still plenty to choose from!


Queens are larger mattresses, at 60 inches wide and 80 inches long. This means a queen bed may be right for you if you’re a taller single sleeper or a couple with a smaller size room. Queen mattresses are also easier on couples’ budgets than their larger counterparts, king mattresses.


The standard king-size bed measures 76 inches in width and 80 inches in length, providing ample space for couples who prefer more room to relax. King mattresses are an excellent choice for larger bedrooms, particularly those exceeding 12 by 12 feet, as they help create a balanced and spacious aesthetic.

California King

The California king bed is a variation of the standard king mattress, with a unique size of 72 inches in width and 84 inches in length, equivalent to six by seven feet. This size is especially well-suited for taller individuals standing over six feet or couples who appreciate additional space at the foot of their bed, such as for sharing it with pets.

Twin vs. Full-Size Mattress FAQs

How do you pick between a twin and full-size mattress?

If you need help determining what dimensions to pick for your new mattress, consider your room size and your height. Those with smaller rooms, such as dorm rooms or studio apartments, may choose a twin or twin XL for compact spaces. Those with larger rooms can go with a full bed.

Taller individuals should consider a twin XL or full XL. For example, if you’re six feet tall and sleeping in a dorm room, the twin XL might be the right mattress size for you, as it will accommodate your height without taking up too much space in your room. 

A full XL bed could be right for you if you want a bed longer than the standard full but with the same width. 

Is a twin-size mattress suitable for taller sleepers?

Both twin and full beds may pose challenges for individuals taller than six feet. With standard lengths of 75 inches, these sizes are generally more accommodating for smaller body frames. Nevertheless, if you are on the taller side and dealing with space constraints, opt for a twin XL mattress instead of a standard twin. The added length of a twin XL can offer a more comfortable sleeping experience while still fitting in compact areas.

Making Your Choice: Twin vs. Full Mattress Options

In conclusion, when deciding between a twin and a full-size mattress, you must consider your needs and space constraints. Understanding the distinctions between these mattress sizes can simplify your choice. For those with modest living spaces, a twin mattress can provide cozy comfort, while those seeking a bit more room to stretch out might find the full-size bed a worthwhile upgrade. Your decision ultimately hinges on your unique preferences and lifestyle.

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