Pillows and Mattresses

A Guide To Mattress Firmness

Examining the subject of mattress firmness and softness is something most people never give a deep level of thought to. When it comes to how a mattress feels, the matter is entirely subjective. Even when two people say they enjoy firm mattresses, their individual ideas of what “firm” means can be miles apart. So, while giving concrete definitions to what constitutes soft or firm is nigh impossible, we can explore the specifics of how mattresses are made to achieve the desired result, how they are marketed, and which ones may be best for your body type and sleep style.

But first, what do we mean when we talk about softness and firmness? In a loose sense, the terms refer to how much “give” a specific mattress has. A mattress that’s more soft will allow you to sink more than one that is firm, which will instead do more to maintain the level of its surface. You can feel this difference the moment you lay down, and can usually tell after one night whether or not your mattress is a good fit for your needs and preferences. 

In simpler terms, imagine it as the resistance of a mattress. The firmer the mattress, the more it will resist the weight of your body. A softer mattress will still offer resistance, but less so, and as you sink, it will hug you to a degree.


Trying to gauge the precise levels of soft and firm hasn’t been a major concern of manufacturers until somewhat recently, thanks partly to online shopping. In those foggy days, before you could shop from your favorite stores with a few clicks of a mouse, furniture stores would let you try the mattress in-store to get a good feel for it. That’s still the case today, of course, but with more of us opting for the ease of online shopping, we don’t get the chance to experience the resistance of any given mattress first hand and can’t even touch it until it arrives at your door.

While you can put mattresses into three broad categories (soft, medium, and firm), capturing more nuanced assessments is difficult because, again, it boils down to personal preference and perception. Individual manufacturers may have their own scales, but attaching a numerical value to resistance levels is far from useful if you don’t have something for direct comparison. It’s the same with online reviews: what does the phrase “softest bed I’ve ever had” mean to people who didn’t write it? 

A good mattress, regardless of how firm or soft it is, will keep your spine aligned while you are sleeping. This means keeping your back, neck, shoulders, and hips in their natural line whether you sleep on your back or side. The support a mattress gives you will achieve this without putting undue pressure on your joints. This can be done with any style of mattress and depends more on your physical health.

It’s also important to note that when we talk about a mattress is soft or firm, we aren’t discussing one having higher levels of support than the other. All mattresses offer support for your body—that’s what they’re made to do, after all—it’s just that how they support your weight differs with their structure. How the mattress is structured is what determines how soft or firm it will be.

Rather than try to assess what different levels of firmness mean, this guide will instead describe how mattresses are made soft or firm and what factors about yourself dictate your own sleep needs.

What Makes A Mattress Soft? What Makes One Firm?

Earlier, we briefly mentioned three simplified levels of mattress firmness. No matter where your preferences fall on that scale, you’re ultimately looking for the same thing: proper spinal support. If we imagine softness and firmness being on extreme opposites of a scale, we get a sense that they differ wildly in how they deliver support. So it follows that how they must use materials exclusive to their levels as well?

Surprisingly, that isn’t the case at all. Any of the materials that you use to build the core of a mattress, be it springs or specialty form, can be used to deliver any level of firmness. How much support they give is determined by density and tension, and not so much the materials themselves.

To some degree, marketing can be blamed for misconceptions about specific types of materials used to build mattresses. Despite how bouncy they may be, springs can be engineered to have little give or lots of give, covering both ends of the spectrum and everything in between. The same can be said for foam and other fillers. It’s not uncommon for people to think that springs must result in a firm mattress and foam a softer one, but it isn’t so simple.

MattressConstructionIt’s important to dismantle this misconception because doing so reinforces the fact that there is no way to accurately gauge whether or not a mattress will be a good fit for you by simply looking at it or its construction. Materials shouldn’t be viewed as a telltale sign any more than an arbitrary number or random review.

Who Needs A Soft Mattress?

When you first lay down to rest on a soft mattress, you’ll notice that it allows you to sink much more than a medium or firm mattress. While it does have to give, the mattress will also use resistance to try and match the contours of your body as a means of providing support. The resulting give only results in a few inches of sinking at most. Though the descriptor “soft” sounds more comfortable, they aren’t inherently better than medium or firm mattresses.


In fact, there is such a thing as a mattress being too soft. This happens when the resulting give doesn’t provide adequate support, causing pain in points throughout the spine. You may not feel it when you’re falling asleep, but you certainly will when you wake up. The soreness can persist for hours or even wake you up in the middle of the night.

One of the key factors in determining if you would benefit more from a softer mattress is your weight. As a rule of thumb, a softer mattress will be a better fit for a lighter person. With less weight, a softer mattress will be better able to match and support your contours. By contrast, a lighter person may not have enough weight to get any give from a firmer mattress, leaving their spine out of alignment and resulting in discomfort. If you’re currently using a firm mattress and have back pain, it may be a sign that you should switch to a softer mattress. 

Softer mattresses tend to be kinder on those with chronic back and joint pain, too. As such, they are a popular choice for those with arthritis.

But it’s not just your weight that determines how much firmness you may need. Your sleep position plays a large role in it, too. There are three sleep positions: on your back, on your side, and on your stomach. Each one requires different types of support to keep your spine aligned correctly, and since the role of your mattress is to maintain that alignment, sleep position and mattress need to be in sync with one another.

A mattress that is on the softer end of the scale is best for those of us who prefer to sleep on our sides. The greater give allows the hips and shoulders to sink, staying straight with the spine and neck. Because of how the lower spine curves, a softer mattress may have trouble giving adequate support for total alignment.

Who Needs A Firm Mattress?

MattressFIRMThe defining characteristic of a firm mattress is that it has much more resistance than give. It still has give, mind you (and softer mattresses also have some degree of support—otherwise they’d be useless as mattresses), but its function is to hold you up on its surface more than cradle you within itself. You can gauge how firm a mattress is by applying gentle pressure to its surface with your hand or even just a finger. If you feel that the mattress is pushing back more than it is giving way, it’s on the firmer side of the spectrum.

Because they indent less, a firmer mattress is better for someone who weighs more. While there’s no agreed-upon consensus, many buyer’s guides suggest firmer mattresses for those who are over 150 pounds. Of course, the heavier you are the more strength your mattress will need to properly alleviate pressure points throughout your body.

You might think that a softer mattress would be ideal for those who are heavier. After all, their weight would cause them to sink deeper and make them feel more snug. However, this results in poor alignment all around. It might feel nice at first, but in time the poor support would result in joint pain.

On a similar note, side sleepers tend to fare poorly on firm mattresses due to their limited give. If it’s not enough to allow the shoulders and hips to sufficiently sink while keeping the spine straight, side sleepers will feel a high level of discomfort. The limited give is best for back sleepers who need their hips and lower spine supported, which higher levels of resistance can provide. Stomach sleepers benefit from more firmness as well for the same reasons.

Again, these notes about weight and sleep position aren’t an exact science that holds true for everyone. It’s entirely possible (and not uncommon) for how someone sleeps to disagree with these guidelines, yet they still find it comfortable. All the more reason to anticipate some trial and error when it comes time for your next mattress purchase.

This video offers an excellent explanation of how mattresses that are extremely hard or soft create pressure points on your body depending on your sleep position:


Other Considerations

Comfort is your ultimate priority when looking for a new mattress, but it’s likely not the only one. Other factors relating to your comfort as well as your lifestyle can influence your decision. The most common ones are below.


Mattresses are already a high-ticket purchase, but sometimes buyers are surprised at how expensive they can be. We expect specialty mattresses to be significantly more pricey due to the use of higher quality materials and complex builds. Those same factors also mean that softer mattresses are usually more expensive than firmer mattresses. 

Soft mattresses make use of multiple specialty materials at their core. The foam tends to be the most obvious because it’s often used for the topmost layer, but additional layers underneath help support the structure as a whole while still allowing for a good amount of sink. Understandably, such structures can cost more to manufacture.


Are you concerned about how long your mattress is going to last? Regardless of how soft or firm you choose to go, you will be replacing your mattresses throughout your life (or at least, you should be—if the eventual discomfort doesn’t bother you, the eventual awful hygiene should!).

Over time, the weight a mattress bears through regular use will cause it to lose give and diminishes support. This means it will eventually soften. The softer your mattress is when it’s new, the shorter lifespan it will have; thus, you will need to replace firm mattresses less often on average. 

It should be noted that once your mattress begins to weaken, there isn’t much you can do to whip it back into shape. There are ways to make it softer or more firm (which we’ll be getting into in this article), but once the core structure goes, that’s it. Get as much use out of it as you can and replace it once it becomes uncomfortable.

To tie things back in with the previous point, it may be appealing to go for the least expensive option you can. If you do, understand that the costs are low for a reason. In most cases, it’s because the materials used are of low quality. You may not feel it in the firmness, but it will likely result in the mattress having a shorter lifespan.


Don’t laugh! This is a very serious consideration for some people. For them, it’s just as important as a mattress that supports a good night’s sleep (and surveys suggest that the two activities are linked). However, your sleep needs may differ greatly from what makes a mattress optimal for sex.

Looking at using our “soft-medium-firm” range, the best mattresses for sex will fall somewhere between medium and firm. It needs enough strength to support your weight without creating pressure points while still having a slight give with which to offer some bounce and push. This helps compliment rhythmic motions without creating painful pressure points.

A mattress that combines springs with foam is perhaps the best option for sex and sleep. They make use of a layer of foam on top of springs, which allows for the springs to still give sturdy support while the foam absorbs some of the pressure they create (as well as cutting down on their noise, too). Just make sure the foam used is dense. Too little density will result in sinking.

Sleeping single or as a couple

Do you and your partner have the same sleep preferences? If so, mattress buying is a quick and simple task. But if you both have different mattress needs, odds are that one of you has had to compromise for the sake of the other’s comfort. That’s a sweet gesture to be sure, but it’s almost impossible to get a good night’s sleep that way.


This is where medium-range mattresses may come in. While perhaps not the perfect solution, it’s a compromise that you both can make that may bring you both close to better sleep. But in special cases, such as weight disparity or conditions like arthritis, the extreme ends of the firmness scale may be necessary. If this is the case for you or your partner, there are a few solutions worth looking at:

Use two mattresses

If you’re using a King size mattress already, you can substitute it for two Twins. A single Twin is half the width (and the exact length of ) a standard King, so all of your bedding will fit just the same and the mattresses themselves will easily fit your box spring and frame. You and your partner can halves that suits your individual needs.

Use a dual mattress

Though they go by different names depending on the manufacturer, the term “dual mattress” just refers to a mattress that has different firmness on each half. They tend to use springs at their core, the softer side will use layers of foam to create the difference. These are harder to find in brick-and-mortar stores but can easily be located and purchased online.

Use a specialty adjustable mattress

Serta has made its name for innovating the adjustable firmness bed. Using remotes, either side of their bed could be made more or less firm independent of the other. The technology has evolved a lot since they were first introduced and other companies now offer their own variations.

Adjustable mattresses like these can be incredible for couples, but they are also, quite understandably, very expensive due to the underlying technology and complexity that entails. What’s more, they also require much more maintenance than normal mattresses. This can include replacement parts should some component of the mechanism breakdown. These are luxury items and you must be prepared to give them more care than other types of beds.

Your pillows

It’s not about coordinating your bedroom: your pillows could be sending you mixed signals about how effective your mattress is. The thickness of your pillows (also known as their loft) needs to be matched to that of the underlying mattress. Note that this isn’t about how firm or soft a pillow is.

It works like this, you’ll want a thinner pillow (lower loft) for mattresses that are softer and thicker pillows (higher loft) for more firm mattresses. These guidelines aim to help maintain the alignment principles of the mattress itself. If a pillow is too thick or thin for a mattress, you’ll notice the difference in your shoulders and neck right away.

You don’t necessarily need to match the firmness of your pillows with that of your mattress, but you should keep an eye on how well your pillows are holding their shape. Much like mattresses, your pillows will eventually lose support as you use them. If you’ve reached the point where you’re folding one over in an attempt to maintain your comfort, it’s time for a replacement.

Scent sensitivity

New mattresses have a particular smell when you first set them up. The odor is a result of the manufacturing process and only lasts a short while (the releasing and fading of the smell is called “off-gassing,” in case you are curious). For some, this isn’t a problem at all, but for others with sensitivities, the smell can cause great distress. Not only does it make sleep difficult, but it can make simply being in the same room a problem.

Off-gassing is more prominent in softer mattresses. That’s because it’s the result of a breakdown in materials commonly used in manufacturing foam and adhesives. These materials are called “volatile organic compounds” because they eventually break down into gas. This is a major issue with memory foam, and many manufacturers have sought alternatives to produce foam while minimizing off-gassing (which, in most cases, lasts no more than six weeks).

While the smell can be annoying to most of us, those with a sensitivity may suffer side-effects. Most of these are eye and membrane irritation but can include headaches as well. While painful, they aren’t fatal on their own, and the chemicals themselves aren’t known to be inherently dangerous on their own.

If off-gassing is a problem for you, but you still prefer a soft mattress, read as much information as you can from the manufacturer as well as customer reviews. Also know that memory foam is the worst offender, so it’s worth your while to search for mattresses that use alternatives.

Heat retention

We need to maintain a level of warmth while we sleep, but being too hot can be just as disruptive as being too cold. That’s why we prefer certain blankets over others or rotate the ones we use throughout the year to match the changing seasons. But your mattress could just as likely be a culprit in your too-hot nights.

Once again, this applies largely to softer mattresses because it involves memory foam and similar materials. Foam has to be dense by design to support your weight, and the denser it is, the less air can flow through it. The result is a mattress that retains more body heat and is difficult to cool.

Memory foam is the worst offender of the lot due to how it functions. The comfort it provides by molding to the shape of your body is a process that is triggered by your body heat. Because you sink deeper into memory foam, less of your skin is exposed directly to the air, preventing it from cooling down rapidly. 

Cooling down a memory foam mattress can be tricky, but isn’t impossible. For some, opening a window or using a small fan can keep the room cool enough to offset the foam’s heat retention. Another solution is to use a mattress pad, a mattress topper, or both in combination. They work to prevent your skin from coming into direct contact with the mattress itself, limiting how warm it will get.

Look for sleep trials

Whether you buy from a brick-and-mortar store or an online retailer, there’s always a chance that the mattress you bought may not be a good fit and you may seek a return. Unfortunately, simple straight-forward returns on mattresses are uncommon because retailers have trouble reselling them (you’ll be shocked to learn that not many people want to sleep on a second-hand mattress). If you aren’t prepared, you may be stuck with a mattress you don’t want or struggle to offload it on someone else.

Most mattress warranties only cover factory defects and damage not caused by the customer (for example, damage stemming from improper handling during shipping). If you find the firmness isn’t what you’re looking for, you’re out of luck unless you can demonstrate it’s related to damage. Warranties are great, but they usually won’t cover you in cases where a mattress simply isn’t comfortable.

Many retailers (especially those online) offer sleep trials. These offers allow you to return a mattress within a set period after you’ve bought it. The minimum is usually thirty days, which is more than enough time to see how the mattress compliments your body or what adjustments you can make, if any, to make it a better fit.

Always read the terms and conditions of either a sleep trial or a warranty to ensure that you fully understand them. If you don’t, make it a point to have things clarified. Doing so could save you time and money.

Adjusting the Firmness of a Non-Adjustable Mattress

Adjustable mattresses are a surefire way to get just the right level of support for you. Of course, they are also incredibly expensive, putting them beyond reach for most of us to buy comfortably. Thankfully, there are quickie adjustments you can make to a standard mattress should it not meet your needs or if your preferences change over time.

For a firmer mattress, try flipping it over. If you’ve had your mattress for a while now and can feel the level of sink increasing, your first fix should be to flip it over. Unless yours is a specialty build with layers in a specific order, the bottom of the mattress should feel very similar to the top. So, when one side weakens, simply turn it over and try sleeping on the other side.

This works best with spring-based designs. Because foam breaks down at a faster rate to conform to your body, it loses support on both sides almost equally and won’t compensate as well by simply turning it over. This method is recommended for mattresses that were already firm by default. It can also work to extend the life of your mattress.

Please note that some mattresses are designed with a specific top and bottom. As such, only one side is meant to be slept on, and sleeping on the other will be incredibly uncomfortable. 

For a firmer mattress, use a layer of plywood. When a foam-based mattress loses its ability to hold your weight adequately, the only way to give it more support is by strengthening its base. Traditionally, the base of a bed is its frame of box spring, but if you’re already using those, you’ll need to take an additional step.

A layer of plywood can be placed between the base and mattress to help give it more support, but it may take some experimenting to get right. Depending on your weight, a single layer may not be enough. Fortunately, plywood stacks easily and is inexpensive on the whole.

An issue you may encounter with any mattress, soft or firm, is eventual sagging. This occurs when the support mechanisms lose their strength in a specific area, usually the middle. Adding plywood to the base can help to prevent the sag, but only to a certain degree.

There are, of course, two primary issues when using plywood to strengthen a mattress. First, it will not prevent the mattress from sagging any further. It only works as a temporary measure, so it’s best used as during the interim period while you’re shopping for a new mattress. Second, the plywood interferes with airflow around the mattress, which can cause it to retain more heat and promote the growth of mold inside the mattress.

For a softer or firmer mattress, try using a mattress pad or mattress topper. Though sometimes used interchangeably (and despite their similarities), mattress toppers and pads are two different products. Each one works differently to make a mattress more firm or soft.

A mattress pad is, as the name implies, padding that can be fitted to your mattress, not unlike a fitted sheet (in fact, some look just like fitted sheets). They’re usually made with cotton and have a nice plush feel to them you’ll notice the moment you lay down to rest. If you want to add a little more softness to your bed, a pad is a nice option that doesn’t cost much money. 

A topper, on the other hand, is quite different. It is designed to put an additional layer between you and your mattress, and because of this, it is generally firm. Because they are more firm than mattress pads, they hold their position well and are often made without a means to keep them in place. Being thicker means requiring more material, thus toppers tend to be more expensive than pads but are still quite affordable.

PurchaseMattressFirmnessTo summarize: a mattress pad can add a layer of softness to your bed, whereas a mattress topper can help make it more firm. Neither one will save a mattress that’s on its last legs, though a topper can extend its lifespan somewhat. The same concerns you have about your mattresses and blankets, such as the breathability of the material, can have some influence on firmness as well. Take the extra steps to research what a topper or pad is made of before you purchase to see how it will interact with the rest of your sleep setup.

Why Choose A Medium Mattress?

You might have noticed that up until this point we’ve talked mostly about soft and firm mattresses without paying much attention to that happy middle ground, medium. It would be foolish of us to overlook them, so we’re going to give them their section to better highlight their unique strengths and benefits.

The best way to describe a medium-range mattress is one that combines soft and firm qualities. Oftentimes this utilizes the standard spring-based core with a layer of comfort foam on top. You get some of the hugs that accompanies foam mattresses with the strong resistance of a firm mattress. That description is somewhat simple, but it’s enough to help illustrate the following points.

The “best” mix between comfort and support – Again, how these things feel is subjective, so don’t take the word “best” as an absolute term. However, medium mattresses are made specifically to bridge the gap between the two extremes, so they are one of the better options for getting the best of both worlds.

Sometimes, your body type and sleep position may not dictate what mattress is best for you. You may like the gentle hug of a soft mattress, for example, but want the stronger spinal support that comes with a firmer mattress. The medium-range does this well, even better than using a pad on an already firm mattress.

Prevents and eases bed sores – One of the biggest benefits of a medium mattress is that it greatly reduces the development of bedsores. If you spend a lot of your waking time in bed, sores can develop as a result of pressure points from your mattress. This is one of the usual recommendations for memory foam since they apply less pressure, but if you require a firm mattress for your weight, sleep position, or a medical condition, the medium-range can work just as well.

Likewise, even weight distribution is easier on muscles, cutting back on general aches and pains as well.

Distributes your weight evenly – This is an important point for couples that find firmer beds uncomfortable. The natural sink of a softer bed can displace other areas of the mattress. This can make things tricky for those who share their bed with someone else.

Medium-range mattresses are firm at their core, which serves to keep them stable despite the softer layer on top. This stability helps maintain even weight distribution, which prevents the mattress from sinking too much under one partner’s weight and displacing the other as a result.

It’s particularly useful if one or both partners move a lot in their sleep. The core of a medium-range mattress is excellent at isolating motion resulting from the movements of its users. In short, it means you won’t feel every time your partner moves. It also makes for better edge support, which is your ability to sit or rest on the edge without it losing shape.

Technically, firmer mattresses are better at providing even weight distribution, but they may not be a comfortable fit for you. This is really where the previous point shines: a medium mattress won’t make you sacrifice a soft feel in favor of a firm hold.

You shift positions while you sleep – It’s not uncommon for someone to change positions throughout the night, going from back to side or vice versa. Mattresses that are overly soft or firm are unable to adapt to this change and will create undue pressure throughout your body. Medium-range options aren’t adaptive per se, but the combination of soft and firm makes it equally supportive in any position.

It’s this same combination that makes medium-range mattresses a great choice for couples with different firmness needs or who sleep in different positions.

Stomach sleeping – This is the least common of the sleep positions, and coincidentally, is usually discouraged by health professionals. It can be difficult to maintain correct spinal alignment when resting on your stomach, but for some, it feels the most natural way to sleep. Others still find themselves on their stomach at some point in the night without meaning to.

While it’s best to avoid sleeping in this position altogether if it can’t be helped a medium mattress comes closest to evenly supporting the neck, shoulders, hips, and spine. You’re likely to still feel some discomfort, but not as much on other mattresses.

If you take the time to read and understand this information, you can remove the stress and guesswork out of your next mattress purchase. Not only that, but you can save time and money trying to figure out what’s the best fit for you.