Bunk Bed Mattress Sizes: A Guide For Safety And Comfort

bunk bed mattress size

If you’re considering outfitting your child’s room with bunk beds and are looking for the correct bunk bed mattress size, you’ve come to the right place.

In this article, we discuss all the options and help you choose the foundation for a safe and comfortable night’s sleep.

Table Of Contents

Bunk Bed Mattress Size Comparison

bunk bed mattress size


The most common bunk bed mattress size is the Twin. It measures in at 38” wide by 75” long by 5” to 6” thick.

The nice thing about the twin mattress is that it is extremely versatile. It fits most “off the shelf” bunk bed frames as well as regular beds for kids of all ages — including older children, teens, and some adults.

Because they are narrow (just three feet, two inches wide), twin mattresses won’t fit more than one sleeper comfortably unless both are fairly small.

That said, the small size of the twin mattress means that most rooms can accommodate two separate sleeping spaces — either on the floor or arranged above one another (as in bunk beds).

Twin XL

The Twin XL bunk bed mattress size measures in at 38” wide by 80” long by 5” to 6” thick.

The extra five inches on the end of the Twin XL mattress means that it can accommodate a sleeper who is more than six feet tall.

While your young child will be nowhere near that height for some years to come, the Twin XL mattress is the perfect choice for a bunk bed mattress because even into their teenage years, your kids won’t outgrow them anytime soon.

Just make sure that the bed frame you choose (or already have) has enough platform space to allow for the extra five inches of length.


The Full (or Double) bunk bed mattress size measures in at 54” wide by 75” long by 5” to 6” thick.

The extra width gives plenty of room for children and teens to spread out and may even be able to accommodate two small sleepers at the same time (though it’s not usually big enough for two adults to sleep comfortably).

While most bunk beds won’t allow for a Full mattress on the top tier, some frames will have room for a Full on the bottom tier.

Full XL

The Full XL bunk bed mattress size measures in at 54” wide by 80” long by 5” or 6” thick.

Like the Twin XL, the extra five inches on the end of the Full XL mattress means that it can accommodate a sleeper who is more than six feet tall and is a great choice for growing children.

And, again, make sure that the bed frame you choose (or already have) has enough platform space to allow for the extra length and width of the larger mattress.


The Queen mattress measures in at 60” wide by 80” long and can range anywhere from 8” to 14” thick.

Queen mattresses will accommodate two young children, two teens, and are usually the minimum size recommended for two adults.

Unless the frame is custom-made and heavily reinforced, bunk beds will not allow for a Queen mattress on the top tier. That said, some frames allow for a Queen mattress on the bottom and a Twin or Twin XL on the top.


The King mattress measures in at 76” wide by 80” long and can range anywhere from 8” to 14” thick.

Because of the extra surface area, a King mattress can accommodate two adults and a young child if need be (though the adults might feel a bit crowded).

Bunk bed frames will not accommodate a King mattress on the top tier, but specialty frames can be found that allow for a King mattress on the bottom tier and a Twin or Twin XL on the top.

Features Of A Good Bunk Bed Mattress

baby laying on a bunk bed mattress

1) Firmness

When your little one is an infant sleeping in a crib, bassinet, or bedside sleeper, their mattress should be comfortable yet firm. This reduces the chances of Sudden Infant Death Syndrome (SIDS) while still providing them with a good night’s sleep.

As your child grows, they become more mobile and build the strength necessary to maneuver their way out of potentially suffocating situations. When they reach the toddler stage, they don’t need the same level of firmness that infants do.

The same goes for older kids who are more likely to sleep on a bunk bed. That said, while your toddler’s and older kid’s bed doesn’t need to be as firm as an infant’s, it still shouldn’t be too soft.

2) Support

Most child mattresses are wrapped in plastic and made with foam, springs, wool, or latex. All of those options have their own unique features, but they also come with their own unique cautions.

Wool mattresses, for example, may keep your child warm at night, but may also trap and hold more dust than a regular mattress. This extra dust so close to your child’s face may increase allergy symptoms in those who are already susceptible to allergies.

Coil and spring mattresses, on the other hand, offer lots of support — especially for your child’s growing body — but they may not always be the most comfortable.

For a safe, comfortable, and supportive option, Newton Baby mattresses are the right choice. Our beds are made with a Wovenaire® Core, which is composed of 10% yogurt cup material and 90% air, then covered with a 100% breathe-thru, soft, quilted cover.

This combination of materials gives children of all ages — whether they’re sleeping in a crib, a toddler bed, or a bunk bed — the same comfort that foam and latex mattresses provide without the toxic chemicals and allergens.

3) Breathability

Child laying on bunk bed mattress

While many parents place a high priority on breathability for their infant’s or toddler’s mattress, they often neglect that feature when shopping for the right bunk bed mattress. That can be a mistake.

Choosing a mattress that lets air flow freely is essential for the proper temperature regulation of your child’s body. For example, if your child gets too warm, they could overheat.

All Newton Baby Mattresses allow for optimum airflow thanks to our innovative Breathe-Thru technology that enables a child to breathe right through the mattress.

4) Quality Materials

As we mentioned earlier, some brands use harmful materials to make their mattresses. With so many different chemical combinations, it’s important to be aware of what the bunk bed mattress you choose is composed of.

The best way to check any mattress for toxins is to read the label or contact the manufacturer to get more details about their materials.

This ensures that you’re buying your little one a crib mattress, toddler mattress, or bunk bed mattress that’s constructed with quality, non-toxic materials.

At Newton Baby, all of our mattresses are GREENGUARD Gold Certified, which means that the product is scientifically proven to help reduce indoor air pollution and the risk of chemical exposure.

Since children of all ages tend to sleep with their faces close to the mattress, the GREENGUARD Gold Certification is essential for reducing the chances that they’ll breathe in harmful chemicals.

Choosing a bunk bed mattress with this certification may also help children who suffer from allergies.

5) Protection

Bedwetting is very common in children up to five years of age (and sometimes older). That’s why it’s essential to choose a bunk bed mattress that offers protection for these little mishaps.

The best option is to outfit your child’s bunk bed with a 100% washable mattress as well as a cover or pad that’s waterproof or water-resistant and lays securely over the mattress to protect it.

Our Newton Baby mattresses come with a cover that allows you to conveniently zip it off and throw it into the washing machine on laundry day or when an accident happens. Additionally, these covers are made with hypoallergenic materials to provide allergy protection all night long.

Choose The Bunk Bed Mattress Size That’s Right For You

bunk bed mattress size

Choosing the right bunk bed mattress size can be tricky, but with the information in this article, you have everything you need to make the best selection for your family.

At Newton Baby, we take pride in manufacturing only the highest-quality beds for babies, kids, and pets.

Our mattresses are made with the safest materials and come in a variety of types — including the Essential, the Mini Crib, and the Waterproof models — so that your little one can get a good night’s sleep every night without being exposed to harmful chemicals.

Whether you use our mattresses in a crib, a bassinet, a bedside sleeper, a toddler bed, or a bunk bed, you’ll be able to worry less knowing that your child is safe and cozy while they sleep!