Box Spring Buying Guide

October 29, 2021

A box spring is a bed base with a wooden frame and either springs or metal rods that provide support to a mattress. It is a type of mattress foundation. The box spring is usually the same size as the mattress that sits on it.

Ashley Sierra mattress on a gray box spring in a decorated bedroom. The mattress and box spring are labeled.

What's the Purpose of a Box Spring?

So, what does a box spring do? While the mattress provides support to the human body, the box spring ensures that the mattress itself is properly supported. It provides a stable surface for your mattress to rest on and absorbs shock, reducing wear on the mattress. This helps ensure your mattress maintains a long comfort life.

Box springs also raise the height of a mattress to make it easier to get in and out of bed. In a complete bed set, box springs are typically placed on top of a wooden or metal bed frame that's connected to the headboard and footboard.

It's also common to see mattresses and box springs used together without a complete bed. Many sleepers who don't feel the need to have a decorative-looking bed will place their box spring directly on the floor, or on casters that stand on the floor. Depending on what you need, there are different types of box springs.

Do You Need a Box Spring?

Although most modern mattresses don't need a box spring to be comfortable some mattress warranties still require a box spring. In some cases adding a box spring to your mattress enhances the comfort and support you get from your bed. The information below should answer the question, 'Do I Need a Boxspring?'.

A box spring is necessary if:

  • Your mattress warranty requires one, helps to prevent your mattress from breaking down

  • You're using a bed frame (mattresses can't rest on those alone)

  • Your mattress is a traditional double-sided innerspring

  • You need or want the extra height, to make it easier to get into and out of bed

  • You want the added bounce and support a box spring offers

Sometimes a different type of foundation works better, depending on the type of mattress and your personal preferences. Learn more about that in our Foundation Guide.

Related: Which Mattresses & Box Springs Work with Platform Beds?

When Should You Buy a New Box Spring?

Does your New Mattress Need a New Box Spring?

When shopping for a new mattress, you may be considering whether you should buy a new box spring (foundation) as well. Or, you may wonder if it would help to replace your box spring periodically regardless of a new mattress.

It's not always necessary to replace your box spring every time you replace your mattress, but it’s probably a good idea to do so. Box springs do wear out at a similar rate as mattresses. Box springs usually last around 10 years, which is a slightly longer lifespan than the typical mattress.

If a box spring has any major defects like broken slats or noticeable sagging, it won't provide adequate support and you will need a new one. Worn-out box springs can cause your new mattress to sag sooner and create discomfort. Mattress warranties will often be voided if you use a box spring that's broken or sagging.

You should buy a new box spring if:

  • You do not have a box spring or platform bed appropriate for your mattress

  • Your current one has broken slats

  • Your current one has noticeable sagging

  • You’ve already had your current box spring for 8-10 years

Find Your New Box Spring

How to Set Up a Box Spring

Typically box springs come fully assembled, so you would just place it where you want it. Some box spring/foundations, like a smart box spring, that go above and beyond a traditional box spring may have a few parts to put together, but it should be easy assembly with instructions. These are usually metal box springs with a fabric covering that act as a complete foundation.

In a complete bed set, box springs are typically placed on a bed frame that connects to the headboard and footboard. It's also common to see mattresses and box springs used together without a complete bed frame.

Those who don't feel the need to have a decorative-looking bed can simply place their box spring on the floor or on casters, with the mattress on top.

With large mattresses, like a king-size, the box spring can be difficult to maneuver through tight spaces in your home. In this case, it may be beneficial to purchase a split box spring, which is split into two halves.

How to Choose a Box Spring

What type of box spring should you use with your mattress? Well, it's best to start by figuring out what you want and what will work in your home. Here's how to do that:

Measure your mattress and bed frame:

You need to choose the right dimensions for your box spring. You’ll want the dimensions to be the same as your mattress so the box spring isn't sticking out nor the mattress hanging over the edges. Make sure it will fit with your bed frame too if you have one.

For reference, the chart below shows the standard dimensions of each mattress size.




76" x 80"

Cal King

72" x 84"


60" x 80"

Full XL

54" x 80"


53" x 75"

Twin XL

38" x 80"


38" x 75"

Decide what you want your overall bed height to be:

Box springs add additional height to your bed. Mattresses have gotten taller than they used to be, so one way to offset that is to use a low-profile box spring, usually 5 inches in height. On the other hand, if you're looking to make your bed taller, a standard box spring is 9 inches in height.

Choose between split and standard box springs:

When buying a large mattress, such as a king-size, the box spring will also be large. As they're much less flexible, they can be difficult to maneuver through the hallways and doors in your home. A solution to this problem is a split box spring. It'll come in two halves, making it much easier to move it around tight corners and small spaces.

Think about the materials:

If you have allergies, you can find box springs with hypoallergenic materials and covers. There are also organic options, as well as box springs that add back support.

Once you've determined the above, you'll be prepared to decide on the right box spring for your mattress and home.

Consider your mattress type:

If you have a memory foam mattress, you may need something different than if you have an innerspring or hybrid mattress. Box springs were designed for innersprings, and you may have a faster breakdown of your memory foam if you place it on a box spring rather than a platform bed, foundation, or adjustable bed. Foundations can be helpful for adding edge support to a memory foam mattress.

Mattresses with coil systems are ideal for box spring use, although some will do okay on other types of foundations. Your best bet is to consult your mattress warranty.

Check the weight capacity:

Whatever you decide to use to support your mattress, make sure to check its weight capacity. It has to be strong enough to hold up the weight of the mattress and the people sleeping on it.

The Different Types of Box Springs

There are different construction types as well as varying height options and split foundations. Over the last several years, advancements in sleep technology have resulted in mattresses that are a lot taller than they used to be. For this reason, many manufacturers produce low profile box springs. as well as ultra-low profile box springs.

The difference in height is completely aesthetic. There's no difference in the amount of support they provide to the mattress. Whether you use a standard or low profile box spring, you can count on your mattress getting the support it needs.

Ultra-Low Profile Box Springs

Ultra Low Profile Box Spring - 2 inches tall

Ultra-low box springs measure 2 inches in height and are the thinnest of the thin. These box springs are usually just a bunkie board made for all sizes of mattresses. This type of foundation is normally used in platform beds and older wooden frame beds. 

Low Profile Box Springs

Low Profile Box Spring - 5 inches tall

Low profile box springs are about half the height of a standard box spring, measuring between 5 and 5.5 inches in height. They’re good for those who don’t like the rising heights of new mattresses. The comfort doesn't change, low profile box springs are made with the same materials as a standard box spring, and provide just as much support.

Standard Box Springs

Standard Height Box Spring - 9 inches tall

While they come in a variety of different constructions, the standard box spring is usually 9 inches in height.

Coil Box Springs

Coil box springs are the traditional box springs, they have a wooden frame with coils that are evenly spaced throughout. The coils will give your mattress more bounce and can help soften a firmer mattress. They may not offer as much support as other types, especially for more modern mattresses which are usually designed for a more solid foundation. Coil box springs are best with innerspring mattresses.

Zero-Deflection Box Springs

Zero-deflection box springs are the most commonly used because they offer good support for your mattress. They consist of wooden slats and sometimes use wire for more support. They’re much more durable than coil box springs and don’t have as much flexibility. They’re compatible with nearly all modern mattresses. It could be considered a wood box spring.

Semi-Flex Box Springs

Semi-flex box springs give more support with a bit of flex. They're made up of a wooden frame with a metal grid above the slats and are usually the most expensive type of box spring. If you have a heavier mattress (latex and memory foam style mattresses often are) then this may be a good option.

Split Box Springs

Split box springs come in two halves, which makes them easier to move throughout your house. If you have tight corners this can be nice, as box springs aren’t bendable like a mattress. These are usually only offered for larger mattresses, like king size or queen size. Just make sure your bed frame can hold this kind of box spring, it will need to have support in the middle.

Explore Box Springs

Box Spring vs Foundation

These two words are often used interchangeably, but what's the difference? Both provide support to a mattress, and they look the same from the outside. However, box springs have steel springs that add support and shock absorption. They work very well with innerspring mattresses, as that's what they were designed for. They're not ideal for mattresses that don't have a coil system, so latex or foam mattresses. 

Foundations are a more solid frame, made of metal or wood, and encased in fabric. There are different styles, some are designed with slats and some are solid wooden frames without openings. They're more suited to non-coil mattresses, which tend to be heavier. They can support more weight than the springs of a box spring but don't have as much flex.

Protect Your Mattress Warranty

Most manufacturers require that a mattress be supported by a box spring to file warranty claims. An exception to this is when a mattress lies on a platform bed or adjustable base. Since platform beds feature either wooden slats or a deck, the mattress doesn't need the extra support of a box spring. Check out our article to learn more about foundations.

The warranty also requires that the box spring is in good enough condition that it will not damage the mattress.

We're Here to Help You Find the Right Box Spring

At US-Mattress, our team of experts is dedicated to helping you on your shopping journey, whether you're looking for a mattress, a box spring, or the right set of sheets. If you have any questions at all, they'll be happy to help! They know it can be a confusing process and will do what they can to make it easy.

So, if you have any questions about choosing the right box spring, you can call 1-800-455-1052 to speak to a friendly mattress expert who can help you make the right decision.

You can also chat live with a mattress expert by clicking on the purple "Chat" bubble.

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