When buying a mattress, you often think about how the new mattress might fit into your bedroom. But perhaps what we should consider is the dimensions of your mattress’s foundation.
There’s almost certainly no such thing as a foundation that’s so space-efficient it’s the same size as its mattress. Most add on a couple of inches at least, which can be important to keep in mind when you’re factoring in other furniture and walking space.
What is a Mattress Foundation?
A mattress foundation is a base for your mattress. It supports your mattress and protects it from dirt, dust, sliding, and sagging. Common choices include a wooden or metal bed frame, a platform bed, or a metal base.
Using the wrong foundation can cause you to feel unsupported, straining your muscles and causing pressure points to build up. The right foundation depends a great deal on the type of mattress you’re using, as the foundation that supports one type of mattress can damage another.
Foundations to Consider
There’s a variety of foundations available on the market. You can choose one that not only provides excellent support but fits within your budget and bedroom design.
This is the traditional bed frame, with a headboard, footboard, and two side panels that often conceal a box spring or the bottom half of your mattress. The frame typically has slats to support the mattress. If you plan on pairing an older panel bed with a memory foam mattress, you may have to buy additional slats or a piece of plywood for more support.
A box spring is a wooden frame with interior coils, all wrapped up in cloth. It’s often paired with an innerspring mattress to absorb shock and wear and tear. The box spring may also add some needed height, making it easier to get out of bed.
However, it may be falling out of favor. More manufacturers are making mattresses thick enough so that you don’t need a box spring for extra height. Plus, a box spring can damage foam mattresses, unless a piece of plywood is placed between the mattress and box spring.
A platform bed has emerged as a popular alternative to the traditional bed frame. It is a rectangular frame with a flat base and legs that are often detachable. The design usually cuts out the traditional headboard and footboard, though some platform beds let you add them on.
The platform may be solid or slatted. Of the two, we recommend the slatted design for better breathability.
An adjustable bed base offers a freedom that no other foundation can match. Using a remote control, you can raise the head and foot of your bed for greater comfort. These adjustments can alleviate conditions such as acid reflux, back pain, and obstructive sleep apnea. An adjustable bed can even prevent snoring.
What stops many from enjoying an adjustable bed is its high price tag. Most adjustable beds cost around $1,000, which is a lot more than a simple wooden frame that might cost a few hundred dollars at most. And since most adjustable bases are final sale items, many customers opt for a less expensive frame they can return if they’re dissatisfied.
Common Mattress and Foundation Sizes
There are six standard mattress sizes, from a twin size to a king size mattress. The best size for you usually depends on your bedroom size and how much you can budget for a mattress, foundation, and assorted bedding. If you’re shopping for a basic bed frame, you can expect to add on 2 to 5 inches to each mattress’s dimensions.
Twin Size Mattress Dimensions: 38 inches by 75 inches
A twin bed is the smallest size most sleepers can consider since an adult would hardly want to sleep on a crib size mattress. And a twin size mattress is often the next step for a child graduating from their baby bed.
Some parents make the most of available space by using twin size bunk beds in their children’s rooms. An adult living in a smaller room may also want to consider loft beds, a variation where the bottom bunk is replaced with a desk or a set of drawers and shelves.
Twin XL Size Mattress Dimensions: 38 inches by 80 inches
A twin XL mattress offers 5 more inches than a standard twin bed. It’s an excellent choice for smaller guest rooms, as you’ll be able to accommodate all but the tallest of single sleepers. Most college dormitories have twin XL bed frames for this reason, although a few schools rely on full size bed frames instead.
Full Size Mattress Dimensions: 54 inches by 75 inches
A full size mattress is 16 inches wider than the standard twin. If you enjoy having the room to stretch out, a full bed might be the perfect size for you.
However, we can only recommend a full size bed for single sleepers. Two people would have only a bit more than 2 feet of space, which is hardly enough to turn over or change positions.
Queen Size Mattress Dimensions: 60 inches by 80 inches
A queen size mattress is the most popular mattress size. It provides single sleepers with plenty of room to sprawl and couples with enough space to share.
A queen bed can fit in most larger bedrooms without any issues. We recommend a room that’s at least 10 feet by 10 feet.
Some couples may debate whether a queen bed is big enough, or if they should consider upgrading to a king size mattress. Our queen vs. king comparison guide can make it easier to weigh the pros and cons of each.
King Size Mattress Dimensions: 76 inches by 80 inches
The largest standard size mattress you can find is a king size bed. Bigger sizes such as the Wyoming, Texas, and Alaska king do exist. But these oversized options usually have to be custom ordered online.
Sometimes a king mattress is called the Eastern king, to differentiate between the California king’s alternative name of Western king.
If you’re thinking about buying a king size mattress, you should double-check your bedroom’s measurements. Even a space-efficient bed frame can add on 2 to 5 inches to a king’s bed dimensions. Anything smaller than a 12 feet by 12 feet room can feel cramped with a king size bed frame.
And you might want to consider the merits of a split king if you plan on sharing an adjustable bed. A split king is divided into two mattresses, each the size of a twin XL. This division not only allows for a bed with two firmnesses, but it also lets each partner adjust their half without moving the other. You can read more about the two in our split king vs. king buyer’s guide.
California King Size Mattress Dimensions: 72 inches by 84 inches
A California king size mattress is 4 inches longer than a regular king bed, with the tradeoff that it’s also 4 inches narrower. With its 7-foot length, a California king mattress offers the leg room that a tall person needs to sleep comfortably.
As with a king mattress, a California king bed takes up quite a bit of room. Your bedroom should be no less than 12 feet by 12 feet to provide sufficient space for a foundation and furniture such as a nightstand and dresser.
Are you trying to decide between a standard king and a California king size mattress? Our king vs. California king sizes guide breaks down the benefits of each.
Which Foundation Should I Use?
The right foundation for you will depend on what type of mattress you use. If you use the wrong foundation, you can void your warranty and even damage your mattress.
The best foundation for a memory foam mattress is a slatted foundation, with slats no more than 3 inches apart. It allows air to flow through, carrying off excess heat and moisture. Other types of foam mattresses do similarly well on a slatted foundation.
You should never pair a foam mattress with a traditional box spring. Over time, the foam is likely to sink between the box spring’s inner coils, stretching the mattress out of shape. This risk of sagging is why most foam mattresses’ warranties are voided when you use them with a box spring.
If you have a box spring you still wish to use for extra height, try slipping a bunkie board between your mattress and box spring. The bunkie board will provide the consistent support your mattress needs.
On the other hand, innerspring mattresses pair well with a box spring, along with most bed frames. And the foundation you shouldn’t use with an innerspring mattress? An adjustable base.
A mattress for an adjustable bed must be adaptable enough to move with the base’s panels without compromising the mattress’s support and comfort. While foam beds and most hybrid mattresses are flexible enough,, the coils of an innerspring may be bent or damaged if placed on an adjustable base.
Frequently Asked Questions
Technically speaking, yes, since a twin size mattress is 6 feet and 3 inches long. However, that can be quite the tight fit for some sleepers, which is why we recommend a mattress that is at least 80 inches long for anyone over 6 feet. If you’re a tall person who needs a bed that can fit in a small space, consider a twin XL mattress.
No, it’s common for other countries to have different bed sizes. Plus, many of them measure their beds in centimeters rather than inches. That said, many of them are similar to our own, and are sometimes off by only an inch or two.
We always recommend choosing a mattress that’s at least 10 inches thick. Thinner mattresses are more likely to break down within a few years. You're also less likely to feel comfortable or supported on a thin mattress, even when it's new.
Your ideal bed height should leave your feet flat on the floor, with your knees level to your hips, whenever you sit on the edge of your bed. Most are comfortable with a bed that’s between 16 to 25 inches tall. Bed risers can help you raise a frame, if needed.
Yes, a queen size bed is bigger than a double bed. A double is another name for a full size mattress, which is 54 inches by 75 inches. A queen size mattress is 60 inches by 80 inches.
Did We Help?
Your bed is almost always the main focus of your bedroom, so it’s smart to think about what your perfect foundation looks like. Perhaps you prefer a simple, sturdy wooden design, or you want all the comforts that an adjustable bed can provide. Whatever your preferences, the right foundation can help you get a better night’s rest.
This article is for informational purposes and should not replace advice from your doctor or other medical professional.