Will a Twin Mattress Fit on a Bunk Bed? We’ve Got the Answer

Twin Mattress Fit on a Bunk Bed

Having a bunk bed in a bedroom, whether it is for a child or an adult, can be a great way to save space in small or large spaces alike. They are perfect for kid’s sleepovers or overnight guests, but finding a comfortable mattress that fits a bunk bed can be confusing. Many consumers wonder if a regular twin-size mattress can fit a bunk bed. 

The size of a bunk bed mattress depends on the measurements of the frame, but a twin, twin XL, or full-size mattress are common sizes for bunk beds. However, the mattress for the top bunk should be at least six inches thick for safety reasons, while the bottom mattress can be any thickness. 

Bunk beds can be a perfect addition to a compact bedroom, a small apartment, even an RV, but there is no standard bunk bed in which to choose. Read on to discover the many types of bunk beds sold on the market today and whether you should purchase a standard twin mattress or go with a larger one for more room at night. 

Different Bunk Beds Require Different Mattresses

A bunk bed is a bed that may have one or two beds and has a mattress foundation or the base where you place the mattress at the bottom, which is more than 30 inches above the floor. The top bunk usually measures 65 inches in height but could range anywhere from 65 to 82 inches, depending on the type of bunk bed being used. 

Most individuals think bunk beds are normally designed for children, and for the most part, that is true. However, there is a range of bunk beds depending on how much room you have and who will be using the beds. Most bunk beds will use a twin mattress, but they are other types available if you have a teen or adult using the bottom bunk: 

  • Two twin bunk beds—The standard bunk bed for children use a twin mattress on both the bottom and top bunks.
  • Two twin XL bunk beds—Both bunks are explicitly designed to fit the slightly larger twin XL mattresses, which are the same width as the standard twin but as long as a queen- or king-size mattress.
  • One twin, one full bunk bed—Another common option for bunk beds that have a full-size bun on the bottom and a twin-size bunk on top.
  • Two full bunk beds—This option is uncommon but has been used for teenagers who share a room or college students sharing a dorm and need the larger mattress.
  • Loft bunk bed—This option will either have a twin, twin XL, or full mattress on top and then an open space underneath for a desk, play area, futon, or additional storage.
  • Shorty bunk bed—This is a shorter version of the standard bunk bed for younger children who may risk falling out of the top bunk. The top bunk sits closer to the ground and may use a twin or full mattress.
  • Triple bunk bed—Three bunks can actually be stacked on top of each other for three children to share a room. All three are usually twin size and require a taller ceiling to fit the bunk bed’s measurements of anywhere from 75 to 82 inches in height.
  • Triple loft bunk beds—This version also has two top bunks, but they are connected at a 90-degree angle. The bottom bunk is under one of the two top bunks and the other bunk has space underneath. The other top bunk has open space underneath for a desk, play area, storage, or even a small couch.
  • L-shaped bunk beds—This choice has two bunks that are perpendicular to one another instead of being stacked on top of each other. They offer more storage space than a regular bunk bed, but also need more space in the bedroom because of the shape.
  • Trundle bunk bed—This has the beds attached just like the standard bunk bed, but the bottom bunk has a sliding mattress to help save space in a smaller room.
  • Futon bunk bed—Similar to a loft bunk bed, this choice has the standard top bunk but a futon on the bottom instead of a bottom bunk bed. 

The type of bunk bed will dictate the size of the mattress. Yet, if you are unsure which mattress to purchase, you should measure the dimensions of the inside of the bunk before you start shopping for a mattress. That way, you will not purchase the wrong size mattress, which is not just annoying but could also be a safety concern on top. 

Before you think about going mattress shopping, you will need to decide which type of bunk bed variation will work best in your home. Determining who will be using the bunk bed and where it will be placed in the room will influence the type of bed. For example, the triple loft works best in the corner of a room while twin types work anywhere. 

Choosing a Mattress Size for a Bunk Bed

Once you know the type of bunk bed, you have and you measure the inside of each bunk, you can determine if you need a twin mattress or larger. Most bunk beds will use either a twin or twin XL, but there will be versions that can fit the larger full size. You can compare the measurements of the inside of your bunk bed to the measurements below: 

  • Twin mattress–38 x 75 x 6 inches
  • Twin XL mattress–38 x 80 x 6 inches
  • Full or double twin mattress–54 x 75 x 8 inches
  • Double XL mattress–54 x 80 x 10 inches 

You may also find bottom bunks that actually fit a queen mattress, which measures 60 x 80 inches, or a king’s measurements of 76 x 80 inches. Although the larger mattresses give more room, twin-size mattresses are ideal because they will fit in nearly any bedroom as long as you have at least 65 inches of vertical space for the bed’s height. 

Twin XL and full-size mattresses work best for growing teens or adults who live in a studio apartment and need a larger mattress but still save space. A full (or double-twin) mattress can possibly fit two people, but they are still ideal for single sleepers who just need more legroom. A full usually is not comfortable for two people to share restfully. 

Queen and king mattresses are both rare in bunk beds, but they could be ideal to fit two people comfortably on the bottom since they are wider than the standard full. If you have three kids, you could easily fit two sleepers on the bottom and then one on top with this type of bunk bed. There are other considerations for bunk bed mattresses. 

Do Bunk Beds Need Special Mattresses?

Shopping for a bunk bed mattress differs from a regular bed because you need to take into consideration the thickness of the mattress in addition to the size. The top bunk should have a mattress that is between four and six inches in thickness for safety reasons. Having a mattress that is too thin or thick could be dangerous. 

If the mattress is thicker than six inches, it could end up being higher than the protective guard rail and the sleeper could risk rolling over the guardrail onto the floor. A thicker mattress will also leave less clearance between the mattress and the ceiling, and the sleeper could hit his or her head on the ceiling when sitting up in the morning. 

Having a thinner mattress that measures between four and six inches will fit within the top bunk’s guard rail and also be easier for the sleeper to get in and out of the top bunk safely. Thinner mattresses are also easier to make and remake when you need to wash the fitted sheet and replace all the bedding after doing the laundry. 

The bottom bunk does not need a special mattress like the top bunk in terms of size or thickness. Bottom bunks have similar mattress guidelines and safety issues as a standard bed mattress and mattress frame. Therefore, you can use any mattress thickness for the bottom bunk as long as it meets the government’s requirements. 

Other Mattress Considerations

In addition to the size and thickness of your bunk bed mattress, there are safety considerations that can be contemplated before purchasing a mattress. You want to weigh both the quality of the mattress for sleep and safety on both the top and bottom bunk. There are federal standards for bunk beds, but four mattress considerations are: 

  • Low profile
  • Quiet model
  • Lightweight
  • Temperature control 

A low-profile mattress that measures between four and six inches in height, but is still thick enough to provide support and comfort while sleeping. You could add foam coverings if you think the mattress is thin enough for safety but too thin for comfort. If you purchase a bunk bed with high guardrails, you can purchase a thicker mattress. 

Quiet model mattresses should also be considered since bunk beds are ideal for sharing a room. That way, they will not creak when sleeping and wake up the other sleeper. A lightweight, all-foam mattress is ideal for the top bunk because they are safe, quiet, comfortable, and lessens the risk of creaking and waking up the bottom sleeper. 

Temperature control should be considered for top bunks because heat rises and the top bunk will always be a few degrees hotter than the bottom bunk. There are mattresses available with cooling technology, but that means they are also more expensive. That being said, they can do wonders to keep the top sleeper comfortable. 

How Tall are Bunk Beds?

In addition to mattress size, having larger bunk beds may mean they are also taller and need a higher ceiling to fit comfortably. A standard bunk bed usually measures 65 inches in height. However, there are extra tall bunk beds that could measure anywhere from 70 to 82 inches in height and could be dangerous to the top sleeper if crammed. 

Short bunk beds usually measure between 50 and 55 inches tall and are ideal for little children to sleep comfortably and safely. Choosing the right bunk bed depends on the height of the ceiling in your room. Ideally, there should be at least 33 inches of space between the ceiling and the top bunk so the sleeper can sit up and not hit one’s head. 

This is why box springs are not required for bunk beds. A box spring adds height to the bed frame and could make the top bunk dangerously close to the ceiling. Box springs also usually work best with innerspring mattresses, which are mattresses filled with coils. Bunk beds usually work better with memory foam, latex, or hybrid mattresses. 

Instead of adding a box spring or base to a bunk bed, they are made with wooden slats or a Bunkie board that supports the mattress. That way, you can simply place the mattress in the box part of the bunk bed and can remove it if necessary. This also makes it easy to measure the inside of the box to make sure the mattress fits properly. 

Make Sure Your Bunk Bed is Safe

The federal government has specific laws that dictate what a bunk bed is and the rules that must be followed for bunk bed safety. You should make sure the bunk bed you purchase complies with the standards and requirements under federal law. You should also determine that the bunk bed is certified with a Children’s Product Certificate. 

Bunk bed rules are in place for a reason, mainly to ensure that children will not be injured or killed by falling out of the top bunk, trapped between the upper bunk and the wall, or choked within the guardrails or openings at the ends of the bunk bed. There are bunk bed requirements for both adult and child bunk beds, and a synopsis is below: 

  • The top bunk must have two guardrails on each side, and the guardrail next to the wall or on the opposite side of the ladder must run nonstop from each end of the bed.
  • The top of the guardrails for the top bunk must be at least five inches over the top of the mattress.
  • The guard rail away from the wall does not need to run continuously across the bed like the top one. However, it cannot be more than 15 inches in distance from either end of the bed.
  • The fasteners that attach the guardrails must be able to be removed before you can remove the guardrails.
  • The lower bunk mattress foundations must be 30 inches or less from the floor. 

The openings on each end of the top bunk should not be wide enough to pass a wedge block through. As noted, the top mattress should be thin enough so that the guardrail is at least five inches above the top of the mattress. There should also be a five-inch margin that extends at least half the distance from the corner posts on each end. 

You can test the bunk bed for entrapment safety hazards by seeing if a wedge block fits through the spaces between the guardrail and upper bunk mattress foundation. Bunk beds that are made for children must also not have any sharp points or edges. Although not required, you probably also do not want sharp points or edges on adult bunk beds. 

Can Adults Sleep on a Twin Mattress?

Depending on how tall you are, you could probably sleep comfortably on a twin because it is 75 inches in length, or enough for someone who measures up to six feet, three inches. If you desire more legroom, you can purchase a twin XL mattress for an additional five inches, which is the same length as a queen or king mattress.  

Larger mattress sizes should also be considered because they give more space for adults to stretch out for added comfort. Adults should also consider heavy-duty bunk beds that can handle a weight capacity of 250 to 800 pounds on the top bunk. Finally, the top bunk must have enough clearance overhead to sit upright comfortably. 

Bunk beds that are specifically made for children only have a 150 to 220-pound weight capacity on the top bunk and the clearance may be shorter. Therefore, adults should purchase bunk beds that are specifically made for adults to make sure the height and weight specifications are safe, comfortable, and will last for a long period of time. 


A twin mattress fits on a bunk bed, but so other size mattresses fit as well. The size mattress you purchase for a bunk bed will ultimately depend on the bunk bed’s frame measurements.

Bunk beds are an ideal solution for space issues for adults, children sharing a room or having sleepovers, or trying to sleep with multiple individuals in an RV or motorhome. There are many uses for bunk beds beyond a kid’s bedroom, and there are many choices that go beyond the standard twin mattress to maximize your sleeping arrangements.


Hi there! I’m Alex, the one behind this website. I ran and operated a Local Furniture Store in Southern California. The store opened in 2010, during the “Great Recession,” It is still thriving today; however, I have dedicated my time to helping our online customer base. My primary focus is to help you with all your furniture & mattress questions.

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