Ideas + Advice

Kids + Teens

How to Buy a Mattress for a Bunk Bed

The right bunk bed mattress should be designed to keep your child safe, comfortable and fully supported. Here, we're sharing the best bunk bed mattresses of 2026 – plus a few tips to make sure you're buying the best one for your child.

1. Consider Mattress Size

The first step in choosing a mattress for a bunk bed is to make sure it will fit in the top and/or bottom bunk. While standard bunk beds are usually built to hold Twin mattresses, some designs may come with special dimensions to equip a larger bed size on the bottom bunk. If you are unsure about the size of your bunk bed, measure it before buying a bunk bed mattress!

Common sizes for bunk bed mattresses include Full, Twin XL and Twin. Twin size mattresses for bunk beds are the same as non-bunk sizes: 38" x 75". (Add 5 inches to the length, and it becomes a Twin XL.)
If you're using a bottom bunk for an adult or a taller child, you may want one that can accomodate a Full size, which runs  54" x 75".
While the recommended mattress height will vary depending on the bunk bed design, the general recommendation is that a bunk bed mattress should not exceed seven inches in height.

2. Consider Mattress Height

Once you know the size of the mattress, you'll need to take into account the mattress's height.

Because most standard quality Twin-sized mattresses are made with multiple layers of comfort foams and supportive springs, many are often too bulky for bunk beds; trying to fit a regular Twin mattress in a top or bottom bunk will leave little room for climbing in and out of bed and even topple over the guardrails, posing a serious safety risk.

3. Consider Mattress Comfort & Support

While choosing a custom mattress thin enough to fit into a top or bottom bunk without adding too much height is essential, most custom thin bunk bed mattresses lack the support and comfort layers that growing children need.

To make sure that your new bunk bed mattress will provide the same quality designs of a regular Twin memory foam or innerspring mattress, pay attention to the mattress material and construction.

Because of the need to keep height down to seven inches, most bunk bed mattresses are made with either innerspring or foam – but not both. And while it is possible for an all-spring or -foam mattress to provide sufficient comfort for adults, most of the time it isn't enough to provide the pressure-relief and support needed for a growing child's bones.

bunk bed mattress comfort support
For this reason, choosing a bunk bed mattress that's packed with both innersprings and comfort foams – without going over the seven-inch limit – is one of the best decisions you can make for your child's comfort, safety and health.

Mattress Height and Safety Rails

Mattress height plays an important role in keeping kids safe while they sleep. For beds with safety rails—especially bunk beds—a thinner mattress helps ensure the rails remain effective. Keeping the mattress within recommended height limits allows guardrails to do their job while still providing comfortable support.

Best Overall Bunk Bed Mattresses

Best Features: 6" thickness - Medium firm
Size:  38"W x 74"D x 6"H
Verified Customer Review: "I ordered this mattress for the full size bunk beds and the kids liked them. Slept all through the night." - MsPattyP
Best Features: Soft cover - Medium comfort level
Size: 38"W x 74"D x 6"H
Verified Customer Review: "Very comfortable for the bunk bed we got our kids." - El_Mo

Best Bunk Bed Mattresses 2026