How Is Mattress Firmness Measured

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How Is Foam Density Measured?

Quick Overview

Density, or weight per unit of volume, is an important variable for mattresses with foam components. Foam density also affects other factors associated with the mattress, such as durability, motion isolation, odor potential, and cost.

This guide will discuss how density is measured for polyfoam and memory foam mattress layers, and provide buying tips for selecting beds based on density measurements.

What Is Foam Density?

Density refers to how much one cubic foot of foam weighs; it is expressed in pounds per cubic foot (PCF). To calculate density, divide the mass or weight of an object by the total number of volume units. For example, a foam layer that weighs 100 pounds and measures 25 cubic feet has a density of 4 PCF; assuming the foam has a uniform consistency, every square foot of the layer will measure 4 pounds.

Two types of foam are widely used in mattresses made today. Flexible polyurethane foam, also known as polyfoam, is a synthetic material produced from polyol and isocyanate petrochemicals. The other foam type is viscoelastic polyurethane foam, or memory foam, a specialized polyfoam engineered to become softer when it comes into contact with body heat and then return to its original shape when cooled. Polyfoam is relatively inexpensive, and widely used in the support core, or base layers, of mattresses; select models also feature polyfoam in the topmost cushioning layers, known as the comfort layers, or transitional layers between the comfort and support layers. Memory foam, on the other hand, is too soft and not dense enough to serve as a support core material; it is almost exclusively used as comfort or transitional layers.

Additionally, foam density falls into three general categories: low, medium, and high. High-density foam is almost always used in mattress support cores, and may also be used as a comfort or transitional layer. Low- and medium-density foams are only found in the bed’s comfort system; if used as a support core material, these foams would lead to excessive sagging and uneven sleeper support.

Density is used to evaluate both polyfoam and memory foam, but the PCF ranges differ considerably. The table below breaks down PCF ranges for low-, medium-, and high-density polyfoams and memory foams.

MaterialLow-Density RangeMedium-Density RangeHigh-Density Range
PolyfoamLess than 1.5 PCF1.5 PCF to 1.7 PCFMore than 1.7 PCF
Memory foamLess than 4 PCF4 PCF to 5 PCFMore than 5 PCF

Density vs. Firmness and ILD

Some mattress brands use the terms ‘density’ and ‘firmness’ interchangeably, but this is technically incorrect. While density is a weight/volume measurement for individual mattress layers, firmness refers to how soft or firm the whole mattress feels, and how closely the comfort layer material conforms to the sleeper’s body. Firmness is measured on a 1-10 scale, with 1 being softest and 10 being firmest; most mattresses sold today fall between 3 and 8.

The firmness of individual foam layers may also be measured in indentation load deflection, or ILD. ILD is calculated by placing a circular disk measuring 1 foot in diameter on a section of foam that measures about 4 inches thick. The ILD is the amount of weight needed to compress that section of foam by 25%; ILD is expressed in numerals corresponding to the weight. The foams used in mattress comfort layers usually fall between 10 and 20; transitional layer and support core foams usually have much higher ILD measurements.

Although density and firmness are technically different measurements, there is some overlap. High-density foams tend to be firmer and do not conform very closely, while low- and medium-density foams are not as firm and conform more.

How Does Foam Density Affect the Mattress?

The density of foam layers used in a mattress can impact many different aspects of the overall bed. The table below breaks down how low-, medium-, and high-density foams affect some these variables. Our ratings are based on a combination of verified owner experiences and product research and analysis.

Foam DensityLowMediumHigh
DurabilityPoorLow-density foam is more susceptible to sagging and early wear-and-tear, giving mattresses with this material a shorter-than-average lifespanFair to GoodMedium-density foams are more durable than low-density foams, but some sagging and early wear-and-tear may still occurGood to Very GoodHigh-density foam has strong longevity; beds made with this material typically have longer-than-average lifespans
Conforming abilityPoor to FairLow-density foams do not respond to the sleeper’s body temperature as much as higher-density foams, resulting in a minimal amount of body conformingGood to Very GoodMedium-density foams conform fairly consistently, though they don’t provide the same close body hug as high-density foamsVery GoodHigh-density foam conforms closely and consistently to the sleeper’s body, due in part to its high responsiveness to body heat
Pain/pressure reliefFair to GoodBecause low density foams tend to conform very little, sleepers may not experience as much pain and pressure relief; that being said, most foam mattresses alleviate discomfort to at least a noticeable extentGoodMost mattresses with medium-density foams – especially memory foam – provide decent pain and pressure relief for sleepersVery GoodHigh-density foams earn strong ratings for pain and pressure relief due in part to their close conforming ability
Temperature neutralityGoodLow-density foams do not absorb and trap as much body heat, allowing them to sleep cooler than denser foams – but temperature neutrality is still average at bestFair to GoodMedium-density foams trap a fair amount of body heat from sleepers, and will likely be too warm for some peoplePoor to FairHigh-density foams can be major heat traps, and are not recommended for those who tend to sleep warm or hot
SexFair to GoodFoams are generally considered worse for sex than other mattress materials because of their low responsiveness, but low-density foams are springier and may be suitable for some couplesPoor to FairMedium-density foams are not very responsive; as a result, some couples claim that having sex on these materials results in a sinking feeling they liken to fighting with the mattressPoorHigh-density foams are temperature-sensitive and often sink excessively; as a result, many couples complain beds with these foams are not good for sex
Motion isolationGoodMotion isolation is a strength of all foams, but low-density foams tend to minimize the lowest amounts of transferVery GoodMost medium-density foams absorb and minimize a significant amount of motion transferVery GoodLike their medium-density counterparts, high-density foams offer strong motion isolation
Noise potentialExcellentWith rare exception, mattresses with low-density foam are virtually silent when bearing weightExcellentMedium-density foam does not make any noise when bearing weightExcellentNoise potential is an area where all foams excel regardless of density; high-density foams are virtually noise-free as well
Odor potentialFairMost mattresses with foam components produce off-gassing odor when new, but those with low-density foams tend to produce the lightest and least persistent smellsFair to PoorThe denser the foam, the higher the odor potential; most medium-density foams emit stronger and longer-lasting smells than low-density foamsPoorThe strongest and most persistent off-gassing odors are associated with mattresses containing high-density foam layers in the comfort system and support core
Mattress weightLowMattresses with low-density foam tend to be lightest; the average weight is about 50 to 65 poundsModerateMedium-density foam can drive up the weight by a noticeable degree; the average mattress weight is about 60 to 75 poundsHighHigh-density foam is naturally the heaviest; beds with high-density foam comfort layers and support cores typically weigh 75 to 90 pounds, or more in some cases
Average priceLowBecause low-density foam is relatively inexpensive, mattresses with this material have the lowest average price-point: about $500 to $750ModerateMattresses with medium-density foams have middle-of-the-road price-points: about $700 to $950 on averageHighExpect higher-than-average prices for mattresses with high-density foam layers outside the support core: about $1,000 to $1,400

Choosing the Right Foam Density

When selecting a mattress based on the density of its foam layers, shoppers should take their weight into account. Lighter people tend to prefer lower-density foams because they do not experience as much conforming/pressure relief on higher-density materials. The opposite is true of heavier people; sleeping on lower-density foams often leads to excessive sagging and less-than-optimal support.

Preferred sleep position is another important factor. Side sleepers usually need a softer, lower-density mattress that will cushion their shoulders and hips; this improves spinal alignment and alleviates aches and pains. Back and stomach sleepers utilize positions that naturally align the spine, but excessively soft mattresses can sink beneath the heavier areas of their body; this causes the sleep surface to become uneven, and can cause more pressure points to develop.

The table below lists average ratings for different foam densities based on these two criteria.

Sleep PositionIdeal Density for Lightweight Sleepers (Less than 130 lbs.)Ideal Density for Average Weight Sleepers (130 to 230 lbs.)Ideal Density for Heavyweight Sleepers (More than 230 lbs.)
SideLow to MediumMediumMedium to High
BackLow to MediumMedium to HighHigh
StomachMediumMedium to HighHigh

Foam Mattress Density Comparison

Now that we’ve discussed what foam density means and how it is used in mattress construction, let’s look at the density measurements for mattresses sold today. The table below includes comfort layer and support core density figures for some of the today’s most popular all-foam beds, along firmness levels and current price-points.

To read our reviews of these brands, please click the links found in the left-hand column; to view product pages, click the links in the second column from the left.

How to Measure Mattress Sag

Indusrty standards consider depressions less than 1 1/2 inches acceptable and generally not covered by your warranty..

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A sagging mattress doesn’t offer proper spinal support and can leave your back stiff and painful when you wake in the morning. A mattress and springs naturally develops indentations from years of normal use, however, a mattress can also sag prematurely due to manufacturer’s defects. When yours is still under warranty and you want to place a claim with the manufacturer, the extent of the sagging must be accurately measured.

Remove all bedding from your mattress including sheets, pads and foam toppers. The original top of the mattress needs to be exposed so you can accurately measure the depression.

Smooth the top of the mattress with your fingers. This eliminates any possible wrinkles in the fabric that could cause the measurements of the sagging to be inaccurate.

Lay string across the width of the mattress so it reaches from one side to the opposite one. It should cross over the deepest part of the depression. Secure one end of the string to the edge of the mattress with a strip of painter’s tape which does not leave a sticky residue on the fabric when it’s removed.

Walk to the other side of the bed and gently pull the unsecured end of the string until it is taut. Secure your end of the string with a strip of painter’s tape. While most of the string rests on top of the surface of your mattress, it does not make contact where it crosses over the sagging portion.

Pull the steel measuring tape so it extends a few inches from its housing. Place the end of the tape so it touches the bottom of the sagging portion of your mattress alongside the string. Hold the housing upright at a right angle to the mattress. Read the measurement on your tape where it intersects the string. This tells you how much your mattress is sagging.

How Is Latex Density Measured?

Quick Overview

In recent years, latex mattresses have become very popular among sleepers. Density, or weight per unit of volume, is an important consideration for latex mattress shoppers. The density of a bed’s individual latex layers can impact mattress durability, temperature, odor, and other important variables for owners, as well as cost.

In this guide, we’ll explain how density is measured for latex mattress layers and shed some light on how to choose a mattress based on density.

What Is Latex Density?

Density refers to the weight of one cubic foot of material, and is expressed in pounds per cubic foot (PCF). To calculate density, simply divide an object’s total weight by its overall volume. For example, a latex layer that weighs 100 pounds and measures 25 cubic feet has a density of 4 PCF. If the latex has a uniform consistency, then each cubic foot will weigh 4 pounds.

Latex is a liquid extract derived from the sap of rubber tree plants. Due to its natural durability and flexibility, latex has many different industrial uses today. In mattresses, two types of latex are generally used: Dunlop and Talalay. Both latex types differ in terms of their specific processing method, as well as consistency, weight, and other characteristics. A full breakdown is found in the table below.

Type of LatexProcessing StepsConsistencyFeelWeight
Dunlop1.Latex is whipped into a froth, injected into a mold, and baked in a vulcanization oven2.Latex is removed from the oven to be washed, then baked a second time to remove moisture contentHeterogeneousFluffy, foamy material is dispersed across the top of the latex layer, while heavier sediment gathers at the bottomDunlop latex can be engineered for any firmness, but it is usually on the firmer side It may be used as a softer comfort layer or a firmer support core/base materialThe sediment in Dunlop latex pulls down the weight, making the material fairly bottom-heavy
Talalay1.Latex is whipped into a froth and injected into a mold2.The mold is vacuum-sealed, causing the latex to expand to its full shape3.Latex is frozen, which pushes carbon dioxide through the material and forms air pockets4.Latex is baked, then removed from the mold and washed/driedHomogenousTalalay latex has a light, fluffy consistency that is uniform throughout the materialTalalay latex tends to be airier and softer than Dunlop latex foam It is commonly used as a comfort layer material, but rarely used in the support coreTalalay latex tends to be lighter due to its air pockets

Generally speaking, Dunlop latex tends to have a higher density than Talalay latex; this is one of the reasons why Dunlop latex is primarily used as a support core material.

When measuring density, latex falls into one of three categories: low, medium, or high. Density is also used to evaluate polyfoam and memory foam used in mattresses. However, density ranges for these materials vary considerably.

It’s worth noting that most mattress brands offering latex beds do not disclose the density of individual latex layers. This is because firmness and indentation load deflection (ILD) are more commonly used to evaluate how a mattress feels for sleepers (see next section). This is not the case for polyfoam and memory foam mattress layers; brands frequently disclose density specs for these materials.

The comparison table below lists normal density ranges for latex (both Dunlop and Talalay), polyfoam, and memory foam.

MaterialLow-Density RangeMedium-Density RangeHigh-Density Range
LatexLess than 4.3 PCF4.3 to 5.3 PCFMore than 5.3 PCF
PolyfoamLess than 1.5 PCF1.5 PCF to 1.7 PCFMore than 1.7 PCF
Memory foamLess than 4 PCF4 PCF to 5 PCFMore than 5 PCF

Density vs. Firmness and ILD

Some mattress brands use the terms ‘density’ and ‘firmness’ interchangeably. However, this is technically inaccurate. While density is a weight/volume measurement used for individual mattress layers, ‘firmness’ refers to how soft or firm the bed feels as a whole. Firmness is assigned using a 1-10 scale, with 1 being softest and 10 being firmest. Most mattresses made today range from a 3, or ‘Soft,’ to an 8, or ‘Firm.’

Another firmness measurement is indentation load deflection, or ILD. ILD refers to the amount of weight needed to compress a certain material. To calculate ILD, place a metallic disk measuring 1 foot in diameter on a section of material measuring 4 inches thick. The ILD – expressed in numerals – is the amount of weight needed to compress that material by 25%.

The table below lists common firmness and ILD ranges for the latex used in today’s mattresses.

Firmness LevelFirmness Rating (1-10)Latex ILD RangeDescription
Extra Soft1-212 or lowerThe material conforms very closely to the sleeper’s body and sinks significantly
Soft313 to 17The material conforms closely and sinks to a noticeable degree
Medium Soft418 to 22Close conforming, but not as much sinking as softer materials
Medium523 to 26Moderate conforming with some sinking
Medium Firm627 to 33Moderate conforming, minimal sinking
Firm7-834 to 38Minimal conforming and little to no sinking
Extra Firm9-1039 or higherVery little conforming, typically no sinking whatsoever

Natural vs. Synthetic Latex

In addition to density and processing method, latex mattress shoppers should evaluate each bed based on how much natural and/or synthetic latex is used.

Natural latexprimarily consists of the extract from rubber trees, though chemical-based cure packages are also used to generate the foamy material during processing; this is true of Dunlop and Talalay processing methods. Some brands advertise their mattresses as 100% organic, but this label is misleading. The standard certification fororganic latex –known as the Global Organic Latex Standard (GOLS) – mandates the material must contain at least 95% natural latex. Therefore, a ‘certified-organic latex mattress’ still contains at least trace amounts of petrochemical filler.

Synthetic latextypically contains little to no natural latex. The chief components are petrochemicals, such as styrene and butadiene, which are treated with emulsifying agents to reduce surface tension. The resulting material is very similar to natural/organic latex in terms of density and feel, but it tends to be less durable and trap body heat to a more noticeable degree. Synthetic latex is also much less eco-friendly than natural/organic latex.

Blended latexcontains a combination of natural and synthetic latex. The ratio varies by material, but as a rule blended latex must contain at least 30% natural latex; otherwise it should be labeled as ‘synthetic.’ Some brands advertise blended latex as ‘natural latex,’ which is also misleading because the blended latex may primarily consist of synthetic components.

How Does Latex Density Affect a Mattress?

The density of latex layers in a mattress can impact other aspects of the bed, as well. The table below breaks down some of these factors, including temperature neutrality, pain relief, and odor potential.

Latex Density LevelLowMediumHigh
DurabilityGoodLow-density latex is less durable than its denser counterparts, but is still fairly durable and tends to last longer than mattress foamsGood to Very GoodMost mattresses with medium-density latex have an expected lifespan of seven and a half years or longer, which is above-averageVery GoodHigh-density latex is one of the most durable mattress materials available; expect a lifespan of at least eight years
Conforming abilityPoor to FairLatex provides less overall conforming than memory foam; low-density latex is more likely to sink without contouring closely to the sleeper’s bodyGoodMedium-density latex conforms to a noticeable extent, but those seeking a deep body hug should opt for higher-density latex and/or foamGood to Very GoodHigh-density latex is the best latex option for sleepers who prefer close, consistent conforming
Pain/pressure reliefFair to GoodMost low-density latex layers alleviate some aches and pains, but those with chronic discomfort may experience minimal reliefGood to Very GoodDue to its decent conforming ability, medium-density latex offers consistent pain and pressure relief for most sleepersGood to Very GoodMost sleepers find that medium- and high-density latex layers offer comparable levels of pain and pressure relief
Temperature neutralityGoodLow-density latex offers stronger air circulation, allowing mattresses with this material to sleep cooler than those with denser latexGoodMedium-density latex may absorb some body heat, but most find it maintains a tolerable – if not perfectly comfortable – temperatureFair to GoodHigh-density latex can easily trap heat; some mattress manufacturers aerate the material with holes for easier airflow
SexGoodLatex is more responsive than foam, which makes it better for sex; low-density latex offers the most responsivenessFair to GoodMattresses with medium-density latex are sufficiently springy for most couplesFairHigh-density latex is not particularly responsive, and may not be springy enough for some couples
Motion isolationGoodDue to its responsiveness, low-density latex minimizes most – but not necessarily all – motion transferGood to Very GoodMedium-density latex isolates motion transfer fairly well – but not to the same extent as memory foamVery GoodHigh-density latex comes closest to memory foam in terms of absorbing and reducing motion transfer
Noise potentialExcellentDensity does not appear to impact noise potential, as low-density latex is virtually silent when bearing weightExcellentMedium-density latex does not make any noise when bearing weightExcellentHigh-density latex, like its less dense counterparts, does not make noise when bearing weight
Odor potentialGoodMattresses with low-density latex often emit rubbery off-gassing odors when new, but in most cases the smells will dissipate in a matter of days (if not hours)Fair to GoodDenser latex produces more odor than less dense latex, but medium-density latex is not associated with excessively strong or long-lasting smellsPoor to FairHigh-density latex carries the highest odor potential; smells range from noticeably pungent to offensive and persistent
Mattress weightModerate to HighLatex is an exceptionally heavy mattress material, but low-density latex is the lightest option; the average mattress weighs 90-105 lbs.HighMattresses with medium-density latex can be fairly heavy; the average weight is about 100-115 lbs.HighNaturally, high-density latex is the heaviest of the three; the average mattress with high-density latex weighs 110-125 lbs.
Average priceModerateLatex – natural/organic latex in particular – can drive up the price-point of a mattress, though some low-cost options are also available; expect to pay between $900 to $1,300 for a Queen size mattressModerate to HighGenerally, the denser the latex layers, the higher the price; as a result, beds with medium-density latex have middle-of-the-road price-points – on average, $1,200 to $1,600 in a Queen sizeHighLatex mattresses are among the most expensive beds on the market; models with high-density latex are usually the priciest and carry an average price-point of $1,500 to $2,000

Choosing the Right Latex Density

Lastly, latex mattress shoppers should consider two personal factors when choosing a model: body weight and sleep position.

Lighter individuals (less than 130 pounds) typically prefer beds that are softer and less dense because they conform to their bodies more closely. This is especially true of side sleepers, who need extra cushioning below the shoulders and hips in order to align their spines and prevent pressure points from building up. A firmer, denser mattress may not conform closely enough for lighter people.

Heavier individuals (more than 230 pounds) are the opposite. Firmer beds are considered the ideal because they do not sink excessively, unlike softer, less dense mattresses. Back and stomach sleepers do not need extra cushioning beneath the shoulders and hips because their position naturally aligns the spine; rather, they require a supportive, even sleep surface that won’t sag beneath their heaviest areas. As a result, most back and stomach sleepers also prefer firmer beds. Those who weigh between 130 and 230 pounds typically prefer mattresses that combine soft body-contouring and firm surface support.

The table below lists the optimal density ranges for sleepers based on weight and position. Please note these ratings are highly subjective; every sleeper is different, and some may find that different density levels are better for them.

Mattress Firmness Scale & Guide – A Must Read Before Buying

There are quite a few different things that you’d like to account for when you decide to shop for a mattress. Given the fact that this is one of the most important purchases for your bedroom, it’s quite important to make sure that everything is handled properly.

Mattress firmness is one of the key characteristicsto consider before you make a purchase. Finding the right level is critical for your good night’ sleep. If you select a unit which is too soft or too firm, you are unlikely to sleep well, and you could even start experiencing issues with your back.

Luckily, there are quite a lot of excellent mattress companies which offer different levels of firmness. The challenge is that to determine it; you’d have to be aware of a lot of different things, especially if you do not have the option to try it.

What is Mattress Firmness?

Obviously, the first thing you’d like to account for is the essence of the characteristic. Believe it or not, there is a lot of misconception out there amongst potential mattress buyers. They tend to believe thatmattress firmness ratings and supportare the same things.

While the former directly correlates with the latter and they are mutually dependent,there’s a difference. The firmness of the bed is its hardness, put in a very simple way. Is it soft or is it hard? That’s the type of question that you need to ask yourself. It’s subjective and different sleepers will have a different feel.

However, this has become a critical characteristic, and it’s an important metric which is accounted for by every buyer. After all, it determines the overall level of comfort as well as the support that the entire thing is going to offer. Have in mind that mattress size shouldn’t impact your overall firmness feel.

Why Does it Matter?

The firmness of the mattress is a fundamental characteristic which is quite critical for the decision-making process. Not only will it determine the overall level of comfort but it’s also going to have a serious impact on the support of the bed as well.

This is something quite critical. The firmness has an impact over almost every important characteristic that your mattress is defined by. From the comfort and support to the overall performance of the unit, everything could be associated with its firmness.

What Does One Firmness Fits All Mean?

One firmness fits all is a phrase used to describe the type of firmness which is going to suit the wide majority of sleepers. The truth is that about 80% of sleepers would prefer a bed which ranges between 5 and 7 on the firmness scale.

With this in mind, it would be appropriate to assume that 6 out of 10 is the metric that the majority of people would be looking forward to.

Some would argue that there is no such thing and that the one size fits all approach is particularly inappropriate in this regard. This might actually be true, but the wide majority of people truly prefer a medium feel brought by their mattress.

There are a few different examples on the market which would target this particular firmness level only to accommodate the ever so growing market.

However, we strongly suggest that you check the bed first and make sure that it is integral and reliable. The firmness is undoubtedly a critical characteristic, but there are other important considerations that you’d have to account for.

While people tie firmness with support immediately, there are different types of beds. Those who use lower-quality materials, for instance, might be firm and yet fail to deliver the necessary support. That’s definitely something that you ought to consider when you’re making the decision.

Firmness vs. Support

Quite a lot of people regard firmness and support as the same thing. This, as we’ve already mentioned above, is not correct.

The firmness measures the immediate feeling that you get as you first lie down on your mattress.

The support, on the other hand, refers to the way the same keeps your spine in perfect alignment.

You can easily have a rather soft mattress which offers a lot of support or a firm one which is also supportive, but it creates a lot of different pressure points which makes it counterproductive.

When you go ahead and pick your mattress, it is quite important to make sure that you separate the firmness as well as the support and have them both in mind. The firmness is just the way your bed feels.

You would also have to make sure that it’s comfortable, that it relieves pressure, that it’s cool and all the other things of the kind. For instance, a firm mattress might fail to deliver the necessary contouring and, hence, it wouldn’t be appropriate for people who prefer to sleep on their sides. These are just a few of the considerations that you’d want to take into account.

In any case, it’s important to keep all those in mind and make sure that the product delivers a proper feel altogether.

Our Firmness Scale & Chart

Extra Soft (1-2)

This is a type of bed which is incredibly soft. These are those mattresses which are absolutely incapable of delivering proper support. The sinkage is tremendous, and that’s undoubtedly something that you should stay away from. It’s just going to harm your spine, and it’s unlikely to be very comfortable as well.We haven’t reviewed any beds that have this level of firmness.

Soft (3-4)

These are softer (plush) mattresses which usually have a sinkage that ranges from 1.5 to 3 inches. These would usually come in two different forms – deep cushion hug and a traditional deep contour memory foam. These are great for people who prefer to sleep on their sides. They are, however, not ideal for back and stomach sleepers.

Medium (5-6)

Medium-balanced beds are the preferred options on the market. It’s estimated that about 80% of the people would fall into this category and most beds we have reviewed have been around this level. You can either go for the average 6 or use something softer in the face of 5 out of 10 on the mattress firmness rating, depending on your personal preferences. Both types are ideal for different kinds of sleeping positions as well.

Hard (7-8)

These are slightly firmer to firm mattresses, and they provide a little less hug as well as sinkage than the medium ones. There are certain exceptions, however, but the truth is that these accommodate people who prefer a little more firmness underneath them. However, the majority of people would find them a bit harder.

Extra Hard (9-10)

These are mattresses which are extra firm. In fact, very few beds would go within it, and there are some therapeutic ones. This is the main reason for which a very limited amount of people would actually prefer this type of units.

How to Understand Mattress Firmness


One of the first and most important criteria that people use when shopping for a mattress is firmness. Even though it’s a term you’ll find used constantly by customers, retailers, manufacturers, and reviewers, it’s rare to find a nuanced discussion of what mattress firmness is and why it really matters.

This guide seeks to change that. We’ll provide a detailed description of firmness and how it relates to numerous other important issues like comfort and support. We’ll address how firmness affects sleeping hot, sex, and motion transfer while providing tips to help you find your optimal firmness level depending on your comfort preferences, weight, and/or sleeping position. Keep reading to get the full low-down on everything you need to know to be a mattress firmness expert!

What is Firmness?

Firmness is a way of describing the feel of a mattress specifically in terms of comfort. Sleeping on concrete would be one extreme level of firmness, while an opposite extreme would be like floating on a cloud. Firmness is often said to be very subjective because what may feel comfortable to one person can be uncomfortable to someone else. For this reason, it is common to see mattresses offered in a number of different firmness levels to allow customers to find a model that will suit their preferences.

Is Firmness the Same as Support?

Firmness isnotthe same as support. This is an important point to emphasize. Support refers to how well a mattress promotes spinal alignment. Firmness refers to the comfort feel of the mattress and how hard or soft it is. While there can be a relationship between the two, it is helpful to think about them separately. A mattress that offers pressure point relief and keeps the spine in proper positioning is supportive regardless of how hard or soft that mattress is. While firmness can be highly subjective, support is not.

The Firmness Scale

Terms like “extra firm,” “medium-firm,” “plush,” and others are used constantly in describing different mattress models, but sometimes it can be hard to know what to make of these terms or to know how they apply when comparing mattresses produced by different companies. As a result, we often refer to thefirmness scale, which is a way of rating mattress firmness from 1-10. Below you can find an overview of this scale:

  • 1 (extremely soft):maximum softness with lots of sink; this type of extra plush mattress is rare
  • 2-3 (soft):quite soft and plush with definite sink.
  • 4-6 (medium):common firmness level that offers a middle-ground with some plushness but more limited sink.
  • 7-9 (firm):much harder mattress with only limited softness and sink.
  • 10 (extremely firm):no softness, plushness or sink; this type of extra firm mattress is rare.

The Firmness Scale In-Depth

In this section, we’ll offer more detailed information about these general firmness levels including about how they can influence support and the types of sleeping positions best suited for them.

Softest (1-3)

A 1 on the firmness scale is extremely rare, but many mattresses are offered in the 2-3 range.

Support:because their softness allows them to conform closely to the body, very soft mattresses can help to relieve pressure points and keep the spine aligned. However, the flip side of this is that for many people, there is simply too much sink and contouring, and the result can be to induce an excessive curvature in the spine.

Sleeping positions:of the main sleeping positions, a very soft mattress is usually best for side sleepers. Side sleepers tend to have more pronounced pressure points at the hips and shoulders and can benefit from more cushioning at those points. For the majority of both back and stomach sleepers, the amount of sink in a very soft mattress can draw the spine out of alignment.

Medium (4-6)

Support:these medium-firm mattresses usually offer the best overall support because they have enough contouring to reduce pressure points while not permitting excessive sinking into the mattress. Spinal alignment for most people is best maintained on a mattress of this firmness.

Sleeping positions:Sleepers in all positions tend to do well with medium-firm mattresses, and these mattresses also tend to work best for combination sleepers (who sleep in multiple positions) and couples who may not sleep in the same position.

Firm (7-10)

Support:many mattresses at this firmness level can still offer sufficient support. While they don’t have the deep contouring properties of softer mattresses, there is often enough cushioning to prevent problems at pressure points.

Sleeping positions:Some side sleepers may have a hard time on these mattresses, although often there usually is sufficient pressure point relief. Some back and stomach sleepers may find that this higher firmness helps prevent their abdomen from sinking too deeply into the mattress. The mattresses at the highest range of this group, though, are rarely comfortable for sleepers in any position.

Why Does Firmness Matter?

Some people may just take it as a given that firmness is a key consideration when shopping for a mattress. But we know that our readers often want to go deeper and understandwhy, so let’s delve into the big reason for why firmness matters:comfort.

It’s hard to overstate the importance of comfort. An inviting, cozy mattress plays a huge role in getting a good night’s sleep. If the first thing you’re thinking about when you get into bed is how uncomfortable you are, it’s unlikely that you’re going to sleep well. Additionally, having a welcoming mattress plays a role in your broader sleep hygiene. Experts recommend developing a routine around sleep that includes a sleep environment that induces relaxation and peace of mind. Having a comfortable mattress is a big part of forming that sleep environment.

Comfort also matters because it can play a role in whether or not you wake up with aches and pains. If you spend hours every night in an uncomfortable position or trying to contort your body to get comfortable, it’s typically only a matter of time before you start feeling the effects. An uncomfortable mattress is also probably not providing you with the support you need, increasing the risk for back issues and consistent soreness in the mornings.

Finding Your Optimal Firmness Level

With that background about mattress firmness in mind, we can start to address how to determine what type of firmness level is the best fit for you. There are several different criteria or ways to approach making this determination.


The first way of selecting the firmness level for your mattress is based on your own perceptions of comfort. As we mentioned, firmness is subjective, and no one knows better than you do what kind of mattress feels good.

As a point of reference, start by thinking about your current mattress. If you know where it falls on the firmness scale, think about whether it’s right for you or whether something softer or firmer would be better. Think also about any experiences that you’ve had on other mattresses such as at hotels or when staying with friends as a guest. You don’t need to know the exact firmness of those mattresses to be able to get a sense of whether your preference runs toward soft, medium, or firm. This is especially true if you have a more extreme preference like a very plush or very hard bed.

While we provide a great deal of general guidance about the type of firmness levels that are normally best for sleepers in certain positions or weights, remember not to discount your own experience. If you know that you’ll only be comfortable on a mattress with a particular feel, go with what you know.


Mattresses respond to the weight and pressure of the body, and as a result, the weight of a sleeper can influence how a bed feels and what firmness level usually provides the most restful night’s sleep.

Sleepers who weigh less than 130 poundsshould err toward a mattress near the softer end of the firmness scale. The reason for this is that a very firm mattress is unlikely to offer much give or contouring at all for a person at this weight. In order to get the benefits of pressure point relief, most lighter sleepers need a more plush mattress in the 2-5 range on the firmness scale.

Sleepers who weigh between 130 and 230 poundsnormally do best with a medium-firm mattress that falls in the 4-6 range on the typical firmness scale. At this firmness level, there is enough cushioning to create a comfortable and supportive sleep surface without the risks that come from a much softer or firmer design.

Sleepers who weigh over 230 poundsshould typically opt for a firmer mattress design, ranging from 6-8 on the firmness scale. Because heavier people put more pressure on the bed, the level of sink can become exaggerated on very soft mattresses. A firmer model can still give cushioning without a risk of the mattress comfort layer bottoming out and failing to offer sufficient support.

Sleeping Position

Another way that you can home in on an appropriate firmness level for your mattress is by considering your sleeping position.

Side sleepershave more exaggerated pressure points at the shoulders and hips and usually need a slightly softer mattress in order to cushion those areas and keep the spine in proper position. For most side sleepers, a soft to medium-firm mattress works best, ranging from a 3-7, with most people getting the best results in the middle of that range. More guidance for side sleepers can be found in our guide to the Best Mattresses for Side Sleepers.

Back sleepersstart out in a position that tends to be good for the spine, but they do need support around the low back in order to make sure that the natural curve of the low back does not get exaggerated in any direction. For this reason, we usually advise that back sleepers select a mattress in the 4-7 range on the firmness scale. Further guidance for back sleepers can be found in our guide to the Best Mattresses for Back Sleepers.

Stomach sleepersnormally should avoid mattresses with excessive sink. Because the abdomen and pelvis will usually sink more than other parts of the body, this can put the body in an unhealthy “U” shape. Most back sleepers get the most comfort and support from mattresses in the 4-7 level with a general preference toward the higher end of that range. Additional guidance for stomach sleepers can be found in our guide to the Best Mattresses for Stomach Sleepers.

Combination sleepers, or people who regularly sleep in 2 or more positions, frequently have the best results when using a medium-firm mattress in the 4-6 range. The reason for this is that a medium-firm mattress has the most flexibility and ability to provide comfort across a range of positions. More guidance for combination sleepers can be found in our guide to the Best Mattresses for Combination Sleepers.

Other Important Considerations

In addition to affecting your comfort, firmness also influences other important elements relating to the performance of your mattress, including the following:

  • Sex:mattresses that are extremely plush or extremely firm may pose barriers to frequent sexual activity. If a mattress is too soft, partners may sink into it too much, preventing movement on the bed. If it is too firm, it may be very hard to comfortably assume many sexual positions. In most cases, a medium-firm mattress is best for facilitating sex. Read more about this and find specific recommendations in our guide to the Best Mattresses for Sex.
  • Sleeping hot: too much sink or contouring can limit airflow around the body. This can cause heat to buildup in the mattress and on the skin, which is also known as “sleeping hot.” This is primarily an issue with plush mattresses and those that are made with certain materials (such as memory foam) that more closely contour to the body.
  • Motion transfer:this refers to how much movement on one side of the bed is felt on other parts of the bed. A bed that permits a lot of motion transfer may cause people who share a mattress to be awoken or disturbed by the movement of a partner. Mattress that offer more contouring to the body usually have less motion transfer as plushness and contouring can isolate motion. In addition, a very firm mattress that does not respond much to the body’s movements at all also usually will not have much motion transfer. The level of motion isolation is also directly affected by the type of material used to build the mattress.
  • Edge support:for people who regularly sit on the edge of the bed or sleep near the edge, edge support is an important consideration. Remember that most mattresses are weakest at the edge, so if a mattress is already quite plush, it is likely to offer even less support around the rim of the bed. People who prioritize edge support usually should err toward a firmer mattress overall.

Firmness FAQ

As you think about mattress firmness, you may have a whole host of questions. We’ve tried to address the most common of these in this section, but if you have a question we haven’t covered, please contact us!

What is universal comfort? Does it exist?

Universal comfort is the “one size fits all” of the mattress world. It is the idea that a mattress can be designed to be comfortable for everyone. In truth, given the subjectivity of mattress firmness and comfort preferences,there is no such thing as universal comfort. It is possible to design a mattress that will work well for a majority of people (for example, most medium-firm mattresses), but the idea of truly “universal” comfort is hyperbole at best.

Does the firmness level affect durability?

Generally not. Durability is influenced predominantly by the quality of the design, materials, and workmanship that goes into a mattress. The only way that firmness can affect durability is that some mattresses, especially firmer mattresses, may have more margin for error to lose firmness as they suffer from wear-and-tear over the years. A mattress that is already quite plush could become wholly unsupportive if its components start to wear out. But a firm or medium-firm mattress may still retain sufficient firmness for a period of time even as it loses its full original firmness.

How can I test out a mattress to see if it is the right firmness level for me?

If you are shopping for a mattress in stores, you can lie down on a mattress to see how it feels. If you do this, we recommend that you stay on the mattress for at least 10-15 minutes to truly gauge how comfortable it is for you. Also, make sure that when you test the mattress that you lie down in the sleeping position that you normally use so that you can get an accurate representation of its comfort in your specific case.

If you are shopping online, you generally are not able to see how the mattress feels before you buy it. Instead, most online retailers offer an in-home sleep trial. This means that you get to sleep on the mattress for a period of time (often 100 nights or more) with an opportunity to return the mattress for a full refund if it isn’t to your liking. For more about sleep trials, check out our guide, How to Buy A Mattress Online.

What if my partner and I have different firmness preferences?

As with most relationship issues, start with communication. You and your partner should discuss both what your ideal firmness is and what you perceive to be your acceptable range. If there is overlap, you can look for a mattress that works for you both. If your firmness needs are wholly incompatible, you can look for mattresses that are offered with split firmness levels so that each side of the mattress has a different feel.

Does firmness affect cost?

Firmness usually does not affect cost; however, there are exceptions. In order to make a mattress more firm, some mattress makers include additional layers of foam or latex, and this can increase the overall cost of the mattress. Check with any specific mattress company or retailer to find out about pricing for individual models.

Are certain mattress types more firm?

As a matter of reputation, memory foam is known for being more plush while latex and innerspring mattresses are considered to be firmer. However, this is highly dependent on the specific design of the mattress and the formulation and construction of the mattress materials. As a result, we encourage you to look at the details of any specific mattress rather than assuming that a mattress will have a particular feel because it is made of a certain material.

What if I’m not sure what firmness level I want for my mattress?

If, as you reflect on past mattresses that you’ve slept on, you really feel lost about the firmness level that you want, we suggest two key things that you can do. First, only purchase a mattress that comes with a sleep trial and a no-hassle return policy. This can give you some peace of mind that even if you buy a mattress that isn’t the right feel, you will be able to return it without penalty. Second, buy a medium-firm mattress. Since this firmness level has the widest acceptance, it is a good place to start. Feel free to contact us if you would like further guidance!

I bought a mattress that is too firm. What can I do?

If your mattress is too firm and you’re still within the timeframe of your sleep trial, return the mattress! If you don’t have that option, you might look into a mattress pad or mattress topper that would go under your sheets. Many plush mattress toppers are available that can significantly change the feel of your bed.

I bought a mattress that is too soft. What can I do?

If it’s not too late to return the mattress for a refund or exchange, do that immediately! But if you can’t return it, your best bet is to look into a mattress topper. These products go above your current mattress and under the sheet. They are made with a wide range of different materials and in many firmness levels, including some that can add firmness to your sleeping surface.

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