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Mattress Foundation Sizes and Dimensions Guide

Mattress Resources
Read Time: 10 minutes

Now that you’ve found the best mattress, you’ll need a sturdy foundation to help it last. A mattress foundation supports your mattress to prevent it from sagging or becoming damaged. Foundations also add additional height to your mattress, making it easier to climb in and out of bed.

In our guide, we will discuss the standard sizes for mattress foundations. We will also talk about the different types of foundations and tips on finding the best match for your mattress type.

Mattress Foundations Sizes and Dimensions

Mattress SizeDimensions (IN)Dimensions (CM)
Twin38 inches by 75 inches96.5 cm by 190.5 cm
Twin XL38 inches by 80 inches96.5 cm by 203.2 cm
Full54 inches by 75 inches137.1 cm by 190.5 cm
Queen60 inches by 80 inches152.4 cm by 203.2 cm
King76 inches by 80 inches193 cm by 203.2 cm
California King72 inches by 84 inches182.8 cm by 213.3 cm

Twin Size Mattress Foundations

Twin size foundations measure in at 38 inches by 74 inches. Standard twin mattresses are some of the most popular beds on the market, but they should be placed in bedrooms at least 7 feet by 10 feet for these foundations to fit comfortably.

Most buyers place these beds in their children’s rooms as they make great bunk bed mattresses. Additionally, twin beds are perfect for adults who have a tight budget and limited bedroom space.

Twin XL Size Mattress Foundations

Twin XL size bed foundations are 5 inches longer than the standard twin. Twin XL size mattresses provide extra legroom and are compatible with rooms at least 8 feet by 10 feet.

Twin XL beds are excellent guest mattresses and are a good investment for college students. Many college dorm rooms include twin XL as the average bed size, so purchasing one will keep you comfy while away from home.

Full Size Mattress Foundations

Full size or double mattress foundations measure at 54 inches by 75 inches. Full size mattresses are wider than twin mattresses and offer more space for growing teenagers or full-grown adults.

Full or double beds are commonly found apartments with limited bedroom space and are a good choice for a 9 foot by 10 foot room. They can also be a compact bed for guest rooms, though some hosts may prefer to spring for a queen that can accommodate two visitors more comfortably.

Parents who purchase a full bed as a mattress for teenagers can repurpose it as a guest room bed when their child move away. Alternatively, some teens may choose to take their bed with them when they move out.

Queen Size Mattress Foundations

Queen bed foundations are 5 inches taller and 6 inches wider than a full. They’re best in bedrooms at least 10 by 10 feet, as bedrooms of this size offer sleepers enough room for other furniture. Queen mattresses are the best option for couples with limited living space since these beds offer 30 inches by 80 inches of space for each person. They also give single sleepers more room to sprawl out and find the most comfortable position.

Despite the queen being the most popular mattress size, some couples may feel crowded on these smaller beds. King and California king mattresses are the go-to’s for couples wanting a bigger bed.

King Size Mattress Foundations

King bed bases measure 76 inches by 80 inches. These foundations take up a great deal of space, and we recommend placing king bed frames and foundations in rooms larger than 10 feet by 12 feet.

King mattresses are the widest of all standard sizes and accommodate couples who need more space. They will even accommodate your little ones on those nights when they sneak into bed with you.

California King Size Mattress Foundations

California king foundations are 4 inches longer than regular kings, but also 4 inches narrower. Cal kings are the longest of all the standard mattress sizes, making them an excellent option for tall sleepers who want extra legroom. However, Cal kings usually don’t work in bedrooms smaller than 12 feet by 12 feet.

Split King Foundations

It’s common for king foundations to be sold as split foundations, such as foundations for split king size mattresses. As the name suggests, it’s a king mattress divided into halves.

Split sizes give sleepers who share the bed freedom to customize their sleep set-up, and these bed frames are also (usually) easier to maneuver and set up. You can more easily carry these foundations through homes with tight doorways, staircases, or narrow corners since they come with two separate pieces.

A split king is two twin XL mattresses placed side by side to make up one large king bed. It’s also worth mentioning, split king platforms can be used with regular king mattresses, as well.

Types of Mattress Foundations

There are several types of mattress supports, including platform beds, slatted or solid foundations, adjustable bed frames, metal platform bases, and box springs. Each type of foundation offers its own set of unique benefits, ranging in durability and affordability.

In the next section, we discuss different variations of mattress supports and talk about what types of mattresses they’re most compatible with.

Mattress Foundation

A mattress foundation has a wooden frame with slats or a solid surface. Most slatted foundations come with a slat kit, containing a non-slip fabric used to slats in place atop of the foundation. These are useful because they eliminate the guesswork with spacing slats, and they offer sturdy, solid support for all mattress types.

Mattress foundations range in thickness, as some foundations are super thin and others are notably thick; however, foundations commonly range between 4 to 18 inches in height.

We appreciate the versatility of these mattress supports because they can work as stand-alone foundations or sit within a bed frame. Many foundations come with detachable, and even adjustable, legs to change up the height of your bed.

Metal Platform Base

Metal platforms contain horizontally-spaced bed slats to support your mattress. These beds are simple to set up, and they provide you with ample under-bed storage space. Metal bases are some of the most affordable foundations, with prices as low as $70.

If you move often, you may enjoy how lightweight metal platforms feel. That said, these mattress foundations are still solid enough to withstand a significant amount of weight. However, we do not recommend these platforms for hybrid or foam mattresses (memory foam or latex) because metal slats can damage foam layers.

Bunkie Boards

A bunkie board is traditionally made with plywood and is paired with a box spring, foundation or platform bed for more support underneath your mattress. A bunkie board is a good purchase for those with memory foam mattresses since the flat platform keeps the bed from drooping. They also work well with slatted bed frames, as they fill space between gaps to create a stable surface.

Platforms Beds

A traditional platform bed has a solid or slatted base so sleepers can lay their mattress directly on top of a platform bed’s surface. Solid bases offer extra support and may be a better option if you have a heavier mattress (like a latex bed), but a slatted surface allows for better airflow and is more ideal for hot sleepers. That said, we recommend using a bunkie board or buying additional slats if your slats are wider than 2.75 inches.

Platform beds are 6 to 18 inches tall and have a sleek minimalistic look. It’s common for these beds to feature additional items, such as footboards, headboards, and storage dressers. Headboard and footboards may take up 7 to 10 inches of extra space.

Adjustable Bed Frames

An adjustable bed frame is a multi-hinged foundation designed to adjust the angle of your head and feet to help sleepers achieve more comfortable rest. These foundations are compatible with all mattress types except older innerspring mattresses since these beds contain less-flexible coils, and their coils may break as you reposition your bed’s angle.

Adjustable beds are a good investment for people who suffer from allergies, sleep apnea, or snoring since they let you sleep at an inclined and can facilitate better breathing. However, the downside to the benefits of an adjustable bed is that they tend to be a bit pricey.

When shopping for adjustable beds, you will find they cost anywhere between $1,000 and $4,500. The number of additional settings and features such as Bluetooth capability, reading lights, and built-in massagers usually come with a price increase.

Box Springs

A box spring is a foundation with a sturdy wooden frame with a layer of steel springs. It is covered in a fabric or cloth material and has a hollow inside, which increases airflow to your mattress. Usually, box springs are placed inside a bed frame, but a few are designed so they can sit directly on the floor.

Box springs are compatible with traditional innerspring beds since the springs absorb the bounce of their inside coil systems. They are not recommended for other mattresses such as memory foam, latex, or hybrids because the coils inside the foundation can damage the supportive foam.

What Should You Do Before Purchasing a Foundation?

Before you begin searching for a new foundation, familiarize yourself with your bedroom size and mattress type. Your bedroom may not be able to fit bulkier foundations with storage space or other add ons, so you may have to opt for a sleek or lightweight alternative. Not to mention, most importantly, your mattress’s warranty guidelines may require you to use a specific foundation with your new bed.

Consider The Size of Your and Bedroom

Some foundations may include additional bedroom pieces such as headboards or footboards. Typically, these items take up about 7 to 10 inches of space, but some can have a bulkier design.

Before you can choose a new mattress or foundation, you have to first consider how much available bedroom space you have to fit a mattress and other furniture. A cluttered bedroom is bad for sleep since it can elicit feelings of anxiety as you lay down for sleep, so you want to find a mattress size to fit nicely within your bedroom.

In the table below, we outline the recommended bedroom dimensions for each foundation size.

Know Your Mattress Type

Always take your mattress’s materials into consideration when shopping foundations. Different mattress types require different support. Below, we discuss the most common mattress types and their compatibility with specific foundations.

Memory Foam Mattresses: We suggest pairing memory foam mattresses with a solid, flat base to evenly support the foam layers. They can also be placed on slatted bed frames, but the slats should be no wider than 2.75 inches to prevent the bottom of the mattress from sagging. Memory foam mattresses should never be placed on a box spring because the coils inside the foundation may cause damage to the foam.

Latex Mattresses: Latex mattresses require a solid or slatted base, as well. Using a slatted foundation will provide proper airflow and breathability to your bed. However, just like a memory foam mattress, you need to keep the slats under 2.75 inches. You can also opt for a solid base since these bases ensure weight is evenly distributed.

Hybrid Mattress: Hybrid mattresses feature foam layers and innerspring coils, so they also pair best with solid or slatted mattress foundations. Platform beds, adjustable bed frames, and bunkie boards also support hybrids well.

Innerspring Mattresses: Innerspring mattresses are made with spring coils and can be placed on most foundations. You can put these beds directly onto slatted foundations or box springs without needing a bunkie board’s additional support.

Other Factors to Consider

Along with mattress type and bedroom size, there are a few more points to jot down before you shop for your new foundation. Below, we offer some tips to make your purchase as smooth as possible.

Shop For Longevity

Ideally, you want your foundation to be long-lasting. A cheap or flimsy foundation may fall apart prematurely. Not to mention, a low-quality foundation can damage your mattress if it provides uneven support. That’s why it’s essential to check the specifications when shopping bed frames and learn more about the materials used to make them.

Stay Within Your Budget

Purchasing a foundation can cost anywhere between $100 to $3,500. Most platform beds and bases are budget-friendly and stay between $100 to $500. However, adjustable bed frames and foundations with electronic features such as under-bed lights, are usually priced at $1,000 or more.

It’s necessary to find a foundation within your budget without compromising your sleep quality. There are inexpensive options available, but we always suggest reading brand reviews to ensure you purchase a durable foundation.

Check The Warranty on Your Mattress

Many modern-day companies recommend a specific box spring or foundation with your newly purchased mattress. Choosing a foundation outside of the company’s guidelines could result in improper support and premature sagging. Though warranties cover damages such as sagging, the manufacturer may void your agreement for using the wrong foundation.

Weight Limits

Before you bring home your foundation, check the weight limits. For some foundations, the combined weight of the mattress and your body weight can be too much to support. Most Cal kings and king-size foundations can hold up to 800 pounds. While twin, twin XL, and full size mattresses can usually hold up to 400 pounds.

Bed Height

Climbing in and out of bed should not be an everyday challenge. You’ll want to decide how high or low you want your foundation to be, so you are as comfortable as possible. If your mattress is too high, it won’t be easy to climb in and out of bed each night. The right bed height enables easy movements.

However, beds too low to the floor require you to squat when you get up, resulting in discomfort. Keep in mind, sheets, memory foam toppers, and the thickness of your mattress contribute to your bed’s overall height.

A bed 25 inches from the floor is usually comfortable for most individuals, and you can try bed risers for a bit of extra height. Typically, a mattress can have 12 inches or more depth, so most people consider purchasing foundations around 8.5 inches to achieve the recommended bed height.

Evaluate Assembly and Set-Up

Some foundations sold online may require self-assembly. Metal frames and box springs are usually easy to set up, but others can be complicated and time-consuming. Instead of struggling with tools for hours, look for companies that offer in-home assembly as an alternative. Some brands may offer complimentary set-up, but others can charge anywhere between $300 to $600 for the service.


Do I need a mattress foundation?

We recommended using a mattress foundation rather than placing your mattress on the floor. Putting your mattress on the ground makes it more accessible to dust mites, bed bugs, and other crawling critters like spiders.

Your mattress may capture moisture more easily on the floor, causing mold or mildew to become trapped inside. A foundation will provide support for you and your mattress by absorbing impact or movement while asleep. Not to mention, foundations keep your bed clean and protected from damage.

What is the standard height of a box spring?

The standard height of a box spring is 9 inches, but box springs can range from 4 to 10 inches thick. Box springs accommodate innerspring mattresses, and in today’s market, these have an average thickness of 8 to 14 inches.

Additional bedroom items such as mattress toppers will also add to your bed’s overall height. Ideally, your mattress should be about 25 inches from the floor, so you can get in and out of bed comfortably.

Can I use a box spring with a memory foam mattress?

You should not use a box spring with a memory foam mattress because the spring coils inside may damage the foam. Box springs work best with innerspring mattresses; the coils inside the foundation work as shock absorbers and distribute the mattress’s weight evenly. The hollow inside of the foundation also provides good airflow and keeps sleepers cool at night.

What type of foundation is best for a memory foam mattress?

Solid or slatted foundations are best suited for memory foam mattresses. A flat, even surface best supports the foam in these mattresses. However, if used with slatted foundations, slats should be no more than 2.75 inches apart.

Wider slats provide inadequate support and can cause your bed to sag. Placing a bunkie board on a slatted foundation will help compensate for the gaps and pair perfectly with your memory foam mattress.

What kind of mattress can I use for an adjustable bed frame?

Memory foam or latex mattresses are the most malleable mattresses and work best with adjustable frames. These foundations can accommodate hybrid or innerspring mattresses, but the coil springs may be damaged when the angle is adjusted.

Additionally, adjustable bed frames are better suited for mattresses with a thickness under 14 inches. Anything more than 14 inches thick will not be as flexible and may not work with an adjustable base.


Finding the perfect foundation is essential to the comfort of your bed. Without the right platform or base, your body and mattress will not be adequately supported, causing sleep interruptions or damage to your mattress. It’s best to buy a sturdy foundation made from durable materials to ensure your mattress is secure.

There are affordable options but, steer clear of flimsy items as they may break easily, costing you more in the long run. By choosing the correct base for your mattress initially, you’ll avoid any bedroom inconveniences and save money.

Meg Riley Certified Sleep Science Coach

Meg Riley is a Certified Sleep Science Coach and a full-time writer focused on sleep and mattresses. She is currently the Editor-in-Chief of Sleep Junkie.

Meg started to focus on the sleep industry in 2018. Since then, she has written over 70+ articles on sleep hygiene, product reviews, and the newest trends in the mattress and bedding industry.

A non-exhaustive list of some of the topics she has written on: the effectiveness of alarm clocks, how to prevent jet lag, the NREM & REM Sleep Cycle, and causes and treatments of Restless Legs Syndrome.

Meg Riley has her undergraduate degree from Pennsylvania State University where she studied Advertising and Public Relations and wrote articles on the student experience for College Magazine.

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