Mattress Foundation Sizes and Dimensions Guide

Last Updated On March 28th, 2024
Mattress Foundation Sizes and Dimensions Guide

Key Takeaways

  • Why Do I Need a Bed Foundation: A mattress foundation is an essential component of your sleep system, providing support, preventing mattress sagging, and increasing the longevity of your mattress.
  • Different Sizes and Thicknesses Available: Mattress foundations come in various sizes, with options for low-profile and high-profile designs to suit different mattress thicknesses and sleep preferences.
  • Match Foundation and Mattress Sizes: When selecting a mattress foundation, choose the size that matches your mattress, and consider the type that best complements your mattress type, as compatibility is crucial for a comfortable and healthy night’s sleep.

Your mattress foundation is as important as your mattress for a good night’s sleep. It can enhance the performance and durability of your bed. Like mattresses, even mattress foundations are available in different sizes.

In this mattress foundation sizes and dimensions guide, we will discuss different types of mattress foundations and their standard sizes available on the market.

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What is a Mattress Foundation?

A mattress foundation is a base beneath your mattress. It supports your mattress, preventing it from sagging, sliding, or getting dirty with dust from the floor. If you place your mattress on a smooth surface like a wooden or tiled floor, your bed may slide. A lack of friction makes the bed slide when you lie on it. Mattress foundations also provide sufficient support to your bed, preventing early sagging.

Mattress foundations can range between 4 to 18 inches in height. They come with or without legs and are grouped under low profile, standard profile, and high profile. If you have a thicker mattress, opt for a lower profile foundation, while a higher profile foundation is a good choice for thinner mattresses.

Ideally, the top of your mattress should be 25 inches from the floor. This way your feet reach the floor when you are sitting at the edge of the bed, making it easier for you to get in and out of bed. People with limited mobility caused by back pain, arthritis, or joint pain may find it challenging to get in and out of too high or low beds, so be careful about mattress thickness and bed height.

Once you have decided on the height of your mattress foundation, it’s time to choose a suitable size and type of foundation.

Mattress Foundation Sizes and Dimensions

Foundation SizeDimensions (IN)Dimensions (CM)
Twin38 inches by 74 inches96.5 cm by 187.9 cm
Twin XL38 inches by 80 inches96.5 cm by 203.5 cm
Full54 inches by 75 inches134.5 cm by 190.5 cm
Queen60 inches by 80 inches152.5 cm by 203.5 cm
King76 inches by 80 inches193 cm by 203.5 cm
California King72 inches by 84 inches183 cm by 213.5 cm

Mattress foundations are available in all six standard mattress sizes. Some foundations have the exact same dimensions as their compatible mattress sizes, while others may be 2 to 3 inches longer or wider than your mattress. If you have less space in your room, it’s better to cross-check with the salesmen or customer service representatives about the exact dimensions of the foundation.

Twin Size Bed Foundation Size

Twin Size Mattress Foundation

Dimensions: 38 inches by 74 inches

Twin size bed foundations measure 38 inches by 74 inches. Sometimes, single adults living with space and budget constraints prefer a twin size. Twin size bed foundations are common in children’s rooms and small bedrooms.

Families with more than one child often use twin size beds on bunk bed frames to optimize their space.

Twin XL Size Bed Foundation Size

Twin XL Size Mattress Foundation

Dimensions: 38 inches by 80 inches

Twin XL size bed foundations are 5 inches longer than the standard twin. The extra length comes in handy for growing teenagers or tall adults. The length of a twin XL is the same as a queen or a king, making it a good choice for tall people who don’t have enough space for a queen.

Parents also prefer a twin XL over a twin in their children’s room because this single bed provides extra legroom. Twin XL sizes are also available as bunk beds. Twin XL bed foundations are common in children’s rooms, dorm rooms, or other smaller rooms.

Full Size Bed Foundation Size

Full Size Mattress Foundation

Dimensions: 54 inches by 75 inches

Full size bed foundations are 16 inches wider than a twin and twin XL, but 5 inches shorter than a twin XL. Full size beds are also called double beds, but they don’t have enough space for two adults. They are suitable for an adult and a child.

A full size foundation is 6 inches narrower and 5 inches shorter than a queen. They are common in areas that don’t have much space such as guest rooms or studio bedroom apartments.

Queen Size Bed Foundation Size

Queen Size Mattress Foundation

Dimensions: 60 inches by 80 inches

Queen size bed foundations measure 60 inches by 80 inches and are the most popular of all standard sizes. The queen is the ideal choice for single sleepers, providing enough space to stretch out and sleep comfortably. A queen can also accommodate couples, allowing 30 inches by 80 inches of space to each sleeper.

Some couples may feel cramped on a queen size, but it is the best option for couples who don’t have large rooms for a king or Cal king. The queen size foundation is common in guest rooms and smaller master bedrooms.

King Size Bed Foundation Size

King Size Mattress Foundation

Dimensions: 76 inches by 80 inches

King size bed foundations are the widest of all standard sizes. King beds are big enough for a couple and can even accommodate children if they want to sleep with parents on some nights.

In fact, two twin XL sizes placed side by side make up a king size. Sometimes king size foundations are sold as a split foundation. It includes two twin XL size foundations, instead of one big king foundation.

Split foundations are easy to maneuver and can be used with split king mattresses or regular king mattresses as well. Split mattresses give both sleepers the option to choose their preferred firmness level on their side of the bed.

California King Size Bed Foundation Size

Cal King Size Mattress Foundation

Dimensions: 72 inches by 84 inches

California king size bed foundations are the longest of all standard sizes. They are 4 inches longer and 4 inches narrower than the standard king. The extra legroom makes them a great choice for tall sleepers. The Cal king size, also called the Western king, is large enough to accommodate a couple and sometimes children as well. You can even find a Cal king in a split variation if you and your partner have different sleep preferences.

Both king and Cal king sizes cannot fit in small spaces, so these larger sizes are common in big master bedrooms that measure at least 12 feet by 12 feet.

Different Types of Mattress Foundations

Different types of mattress foundations are available in all standard mattress sizes. While finding a size-compatible foundation may be easy, it’s critical to find a foundation that fits with your mattress type as well. Not all foundations are compatible with all mattress types. Pairing your mattress with a compatible foundation is crucial for a night of sound sleep and your health as well. You may wake up sore in the morning if your bed is not on the right foundation.

An incompatible foundation may not provide adequate support, causing mattress sag. Sleeping on a sagging mattress misaligns your spine, triggering back pain, neck ache, and muscle stiffness.

Some mattress manufacturers may even void your warranty if your mattress is not placed on a compatible foundation. Usually, innerspring mattresses are placed on a box spring, while latex, memory foam, or hybrid mattresses are placed on platform beds, solid or slatted foundations, or adjustable bases. We recommend checking with the mattress manufacturer about a compatible base for your bed.

The following are the different types of foundations for various mattress types.

Platform Bed

A platform bed is a simple bed frame with wooden slats, solid wood, or a metal grid surface to support your mattress. Slatted surfaces promote airflow beneath the mattress, keeping your bed cooler.

Memory foam, latex, and hybrid mattresses are compatible with platform beds. If you are placing your mattress on a slatted surface, make sure the slats are no more than 2.75 inches apart. Wider gaps provide inadequate support, causing mattress sag.

To compensate for the wider gaps, you can place a bunkie board on the slatted surface and then place the mattress on it. Bunkie boards are a piece of a plywood board placed beneath the mattress for firmer support. They are available in any home improvement store.

Platform beds can be between 6 to 18 inches tall and typically come in the standard bed frame sizes. See also:

Platform beds are available with or without head and footboards. If you are buying platform beds with head or footboards, consider the available space in your room. Headboards and footboards with storage space may take up to 7-10 inches of additional space along with your mattress length. Headboards can be up to 3-4 inches wider than your mattress, though headboard sizes do vary.

When choosing a platform bed, factor in the space you need for other bedroom furniture such as nightstands, a lamp, and a dresser. Ideally, you should leave 2 to 3 feet of space on all three sides of your bed (except the side against the wall). This leaves enough room for walking and doesn’t overcrowd your bedroom.

Our Amerisleep Platform Bed

Our Amerisleep Platform Bed is made of solid wood, providing durable support to your bed. The pinewood slats are oversized and bordered by side rails, keeping your mattress secure. Our foundations are easy to assemble and you don’t need tools to put them together.

Prices of our Amerisleep Platform Bed

Our Amerisleep foundations are 13.5 inches tall and available in six standard sizes.

Twin XL$399
California King$599

Box Springs

A box spring is a wooden frame with a layer of steel coils inside. It is topped with an anti-skid fabric for a better grip, preventing mattress movement. Unlike older models, some modern-day box springs have a steel frame for enhanced support. Box springs can be placed directly on the floor or in a bed frame.

Box springs are most compatible with traditional innerspring mattresses because the coils in the box spring serve as shock absorbers, reducing motion transfer in innerspring beds. They are not compatible with latex, hybrid, or memory foam mattresses because these heavier mattresses may break the coils inside the box springs, causing mattress sag.

Mattress Foundations

A mattress foundation is a wooden box with wooden slats or solid wood across the surface. It’s usually covered by a breathable, anti-skid fabric. Solid wood or slatted foundations are compatible with most mattress types, as they are sturdy enough to bear the weight of heavy latex, hybrid, or memory foam mattresses. Some people may place a foundation on a platform bed for additional support to the mattress. This also increases the height of the bed.

Adjustable Bases

Adjustable beds are the most luxurious of all foundations because they give you the option to elevate your head and feet region using a remote control. Sleeping in this zero gravity position improves circulation, relieves pressure points, reduces aches, and minimizes chances of snoring, sleep apnea, and acid reflux.

Adjustable beds are compatible with all mattress types except innerspring mattresses because the coils at the base layer may break when flexed. All other mattress types are flexible enough to be elevated at an angle, but we recommend checking with the mattress manufacturer before placing any bed on an adjustable base.

Like other mattress foundations, there are various adjustable bed sizes to consider. Smaller sizes of adjustable beds can be trickier to find, but it’s possible to find even a twin or twin XL size adjustable bed.

Queen and king size adjustable beds are popular choices, especially as they can provide couples with custom comfort.

Our Amerisleep Adjustable Bases

At Amerisleep, we sell two adjustable beds: the Amerisleep Adjustable Bed and the Amerisleep Adjustable Bed+. Our Adjustble Bed is a more entry-level base with fewer features, while our Bed+ is the total sleep upgrade.

Our Amerisleep Adjustable Bed can be controlled through a remote or an app on your phone. It comes with special features such as a zero-clearance design and programmable positions.

Our Adjustable Bed+ comes with full-body massagers in addition to all of the convenient features included in our Adjustable Bed. With the Adjustable Bed+, you can enjoy a full body massage while controlling the massager intensity with the remote or an app.

Prices of our Amerisleep Adjustable Bed

Our Amerisleep Adjustable Bed is available in six standard sizes, including the split king option. It is backed with a 10-year warranty covering manufacturing defects.

Adjustable Bed SizePrice
Twin XL$840
Split King$1680
California King$1680
Split California King$1680

Prices of our Amerisleep Adjustable Bed+

The Adjustable Bed+ is available in five sizes: twin XL, full, queen, king and split king. It’s backed by a 25-year warranty.

Adjustable Bed+ SizePrice
Twin XL$1440
Split King$2880

More Mattress and Bedding Size Guides

It’s not just important to choose the right-sized mattress foundation, as you’ll need other appropriately matching bedding accessories.


What is the size of a standard full mattress?

A full mattress, also called a double bed, measures 54 inches by 75 inches. It’s not big enough for two adults but can accommodate one adult and a child. The full size is 5 inches shorter in length than a queen, king, or twin XL mattress, so tall people may find it difficult to sleep on a full size mattress.

What is the standard height of a box spring?

The standard height of a box spring is around 9 inches. Mattresses up to 14 inches thick can be placed on a standard box spring. Ideally, the top of your mattress should be 25 inches from the floor so you can easily get in and out of bed. The height of a box spring ranges between 4 to 10 inches.

Box springs thinner than 5 inches are called low profile box springs. Pair a thicker innerspring mattress with a low profile box spring to avoid the difficulty of getting in and out of bed.

Will a full size mattress fit a twin foundation?

No, a full size mattress is 16 inches wider than a twin mattress so a twin size foundation will be way too narrow for a full bed. All foundations are available in standard mattress sizes. A full size mattress fits a full size foundation, which is easily available online or in mattress stores.

Are bed frames different from mattress foundations?

Yes, bed frames are different from mattress foundations. Bed frames typically include a headboard, footboard, and side rails. Sleigh beds, canopy beds, and four-poster beds are examples of bed frames. Most bed frames can’t support a mattress so they are used with a foundation. In fact, platform beds are the only bed frames with built-in foundations.

How much bigger is a full than a queen size mattress?

A full is not bigger than a queen mattress, rather it is 6 inches narrower and 5 inches shorter than a queen. Since a full bed is shorter than a queen, it’s not the best choice for tall people.  Full beds are a good option in small guest rooms or studios that don’t have enough space for a queen bed.


Your sleep system isn’t complete without the right foundation. Some people place their mattresses directly on the floor, but doing so cuts off the airflow, increasing the likelihood of mold or mildew and heat build-up, which can lead to sleep disruptions. Sleep deprivation affects your productivity the next morning and impairs your health in the long run.

Buying a foundation compatible with the size and type of your mattress saves you money in the long run. Your well-supported mattress lasts long and you don’t have to worry about buying a new mattress for a while.

About the author

Mitchell Tollsen is a graduate student and a freelance writer who’s contributed to the Early Bird blog for three years. Mitchell’s always been fascinated by the science of sleep and the restorative processes our bodies undergo when at rest. The self-titled “Sleep Expert” is always looking for ways to improve his shut-eye, and throughout the years has implemented numerous lifestyle changes and tried dozens of sleep-promoting gadgets to determine the best ways to truly get better rest.

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