Graphic showing all foundation sizes and dimensions
Buying Guides

The Ultimate Mattress Foundation Sizes And Dimensions Guide

    Last Updated
    January 20, 2023
    min read

    Most people consider the type of mattress, pillows, and assorted beddings before everything else. However, finding the correct foundation for your bed is just as important – and it all starts with the correct dimensions.

    This guide will discuss some of the most common types of foundations, whether you need one, and how different mattress dimensions will affect your purchasing decisions.

    What Is A Mattress Foundation?

    A mattress foundation is a solid surface that sits underneath your mattress to protect it from sliding and scratching your floors as well as introduce much-needed airflow throughout the night. This base can be made from wood or metal and may come in various forms, like a slatted foundation or a high-tech adjustable base. 

    Mattress foundations can range from roughly 4-18 inches tall, matching mattresses of various thicknesses. For example, a thick hybrid mattress would best be paired with a low-profile wooden frame to create the right height for getting in and out of bed – a must for people with chronic aches and pains.

    The typical bed base will come in different dimensions to account for various bed sizes, ranging from a standard twin to a king mattress.

    Do I Need A Mattress Foundation?

    While you don’t need a mattress foundation and can use your mattress on its own, they come with many advantages, such as preventing your mattress from slipping and sliding while you sleep. One of the best benefits, however, is the added support. 

    The right foundation can also double as bedroom furniture by providing extra storage space. Some kinds of foundations contain drawers or secret compartments for clothes, books, and other personal items. 

    Mattress Foundation Sizes And Dimensions

    Mattress foundations are typically the same size or a few inches bigger than their mattress counterparts, similar to bed frame sizes. Check the chart below for reference.

    Mattress size

    Dimensions in inches

    Dimensions in centimeters


    38 x 74

    96.5 x 187.9

    Twin XL

    38 x 80

    96.5 x 203.5


    54 x 75

    134.5 x 190.5


    60 x 80

    152 x 203.5


    76 x 80

    193 x 203.5

    California King

    72 x 84

    183 x 213.5


    Twin-Size Bed Foundation Size

    Twin-size mattresses are the smallest beds intended for adults. These are great for college students living in dorms or for single sleepers who don't need the extra inches of space. Their bed foundations are usually a few inches narrower and shorter than other options on the market at just over 38 x 75 inches. 

    Twin XL-Size Bed Foundation Size

    A twin XL mattress foundation measures a little over 38 x 80 inches, giving it a few more inches of legroom than its standard counterpart. These are ideal for tall sleepers who don't share their space with another individual. 

    Full Size Bed Foundation Size

    A full size bed is a more spacious alternative to the narrow twin mattresses, with their foundations measuring 54 x 75 inches. These bases are a little wider than the full size mattress, ensuring that you get ample edge support and don't accidentally roll off the bed overnight. 

    Queen Size Bed Foundation Size

    A queen size bed measures 60 x 80 inches. Foundations should be enough to support at least two people and perhaps even a small child or pet. 

    King Size Bed Foundation Size

    King size beds are the perfect choice for couples who need a little bit more space, and these mattresses have giant foundations to match. Measuring just over 76 x 80 inches, these bases can support up to three people on one bed without much issue. 

    They may take up too much space in tiny rooms, so buyers should take their sleeping area measurements beforehand.

    California King Size Bed Foundation Size

    California king size mattresses are longer and narrower than their more traditional counterparts at 72 x 84 inches, making them the go-to option for taller couples. These foundations have roughly the same footprint as regular kings, so there should be no problems fitting them into a master bedroom. 

    Mattress Foundation vs Box Springs

    One of the biggest hurdles you'll run into is whether you should invest in modern-day box springs or some other type of foundation for your mattress. Luckily, distinguishing between bed bases and box springs is very straightforward.

    Box springs are a type of flat base that contains several rows of spring coils. These are meant to be used with innerspring mattresses since they interact with the bounciness perfectly. However, most manufacturers caution against pairing box springs with other common mattress types and will void your warranty if you proceed anyway. 

    On the other hand, a regular mattress foundation is just a flat surface upon which you can lay your bed. These can come in all shapes and sizes, and some companies even offer a modular base for folks who like to customize their furniture. Mattress foundations tend to be more widely compatible and stylish. 

    Different Types Of Mattress Foundations


    A platform bed is a flexible kind of mattress foundation that can have wooden slats or a metal base. These foundations are common choices for first-timers because they work well with almost any type of mattress, from your regular memory foam bed to more luxurious latex mattresses. 

    This is because platform beds have some of the most varied options on the market, making them an excellent choice for sleepers who are still trying to find their perfect mattress. But that's not all there is to these incredible beds because different base types give you different benefits.

    For example, a platform bed with a slatted base is more supportive and keeps your mattress from sinking or sliding. They’re also easier to take apart, which makes moving these beds easier. Meanwhile, a platform bed with a metal base is sturdy and durable.

    Bunkie Boards

    As the name suggests, a bunkie board is simply a board you can lay over an older bed foundation or box spring. Doing this can raise your bed's overall height to accommodate taller sleepers while providing a flat surface to support your bed. 

    Bunkie boards are best used with box springs, especially if you have non-spring beds like latex mattresses. Adding this layer between your foundation and bed provides protection from potential punctures and holes. In addition, you won't have to shell out thousands of dollars to replace an old-school box spring with bunkie boards.

    Box Springs

    Box spring foundations are wooden cloth-covered frames that contain pocketed coils. These coils act as shock absorbers against the pressure of a person's body weight, making them the perfect choice for folks who prefer the old-school feel of innerspring mattresses. 

    Adjustable Base

    Adjustable bases are the cream of the crop when it comes to bed foundations because of their ability to bend and adjust based on your body's needs. Spinal alignment and comfort contribute to the quality of your sleep, and adjustable frames help you achieve optimal sleeping posture, making micro-adjustments at the touch of a button. 

    However, if you have an innerspring mattress, you may want to steer clear of the popular adjustable bed frame. Bending and flexing the bed's inner coils against their natural curvature can permanently damage your mattress, which reduces back support over time.

    Panel Bed

    Panel beds are a kind of bed frame that has a headboard and footboard combined with a few side panels that partially cover your mattress. These old-school bed bases also contain wooden slats, making them the perfect foundation for more traditional beds with hard underlayers. 

    Panel beds can also be modified to support more modern mattresses with a bunkie board. 

    Things To Consider When Buying A Mattress Foundation

    Bed frames are more than just a stylistic choice that can tie your whole bedroom together – they can also make a bed more supportive and comfortable. That's why you must note all the primary considerations before purchasing. 

    Here are the main things you should note before heading off to your favorite mattress manufacturer for a matching frame.

    Mattress Size And Number Of Sleepers

    Finding the perfect size mattress foundation is crucial. After all, who wants to feel cramped and constricted while they sleep? Luckily, it's pretty easy to figure out the right size foundation. 

    All you need to do is note your existing mattress dimensions and whether you're sleeping with one or more people. The more sleepers there are, the more support your foundation should provide and the bigger it would have to be.

    As a general rule of thumb, your mattress foundation should be larger than the bed itself to ensure enough support at the edges. 

    Bedroom Space

    Whether you're buying a bed frame for your guest bedrooms or your kid's college dorms, you'll need something that doesn't take up too much space. Here's a quick guide to different bedroom dimensions and the types of bed frames that would fit in them:

    Bed frame size

    Bedroom dimensions in feet


    7 x 10 ft

    Twin XL

    7 x 10 ft


    9 x 9.5 ft


    9.5 x 10 ft

    King / California King

    9.5 x 11.5 ft


    Mattress Type

    Compatibility is key when purchasing a new mattress foundation for your bed of choice. Mixing and matching may be acceptable when trying to find the right fit for your sleep style, but it's probably best to stick to tried and tested pairings. For example, a flat or slatted surface would work best with a modern memory foam mattress, while box springs can only be used with innerspring beds. 

    Beyond this, you'll want to keep your mattress thickness and weight in mind when making a purchase. Thicker and heavier mattresses, for example, might fare better with more robust metal frames, while thinner beds are perfectly fine with wooden ones. 

    Key Takeaways

    Mattress foundations are an essential yet often overlooked part of a person's sleeping setup. They can provide extra support, storage space and introduce a little bit of much-needed airflow. 

    However, buyers first need to ensure that they're purchasing the correct size for their mattresses. Luckily, many foundation manufacturers adhere to standard sizes, so finding the right one should be pretty straightforward. 

    Are you looking for the best all-around bed foundation for your new mattress? Check out our selection of Purple bed frames today!

    Mattress Foundation FAQs

    What is a standard foundation for a bed?

    Standard bed foundations are bases with an average height of nine inches. These foundations are best paired with average-sized mattresses for the easiest possible experience getting in and out of bed. 

    How thick should a mattress be for a platform bed?

    A platform bed is best used with a mattress that’s 12-14 inches.

    Is a foundation the same as a bed frame?

    No, a mattress foundation is not the same thing as a bed frame. Instead, mattress foundations are a flat supportive surface upon which people lay their beds, while bed frames may not necessarily have the same base. 


    About the authors

    Cecilia Gillen

    Cecilia brings over five years of writing experience primarily centered around lifestyle and health topics. She has a Bachelor’s degree in Media and Journalism from the University of South Dakota. She’s both an advocate for sleep and a night owl at heart.