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Mattress Firmness Scale Guide: The Softest Mattress to the Firmest Mattress

When Goldilocks wanted to sleep in the Three Bears’ house, there were three beds to choose from, each with a different firmness. To find the best bed, she tried them all. Papa Bear’s bed was too hard, and Mama Bear’s bed too soft, but Baby Bear’s bed was just right.

When it comes it choosing a mattress, the desired level of firmness is a matter of personal preference. Fortunately, mattress shoppers can select from a mattress firmness scale with several different levels of firmness:

The Mattress Firmness Scale

  • Extra Soft
  • Soft
  • Medium
  • Medium-Firm
  • Firm
  • Extra Firm
  • Universal

Choosing a good mattress is a very personal choice. Firmness is partly objective and partly subjective, as you can see in almost any mattress review. The same mattress may feel firmer to one person and softer to another, a factor which bears on customers’ mattress ratings.

What to Consider When Picking Mattress Firmness

There are several factors to take into account when choosing a mattress with the right firmness. These include materials, weight, body size and shape, health conditions, and partner sleeping.

Mattress Materials

There are several mattress types available which are made using a variety of materials. These materials can interact with your body in different ways. Depending on the type of mattress you choose, your preferred level of mattress firmness can change.

Memory Foam

Memory foam was developed from the material NASA commissioned to cushion astronauts on lift-off. Memory foam is heat sensitive and it softens when it warms up. With memory foam, a sleeper’s body temperature can affect the firmness. The density of the memory foam also comes into play. Denser memory foam is firmer when it is cold but softens more when warm — this is what makes it so conforming.

Lighter memory foam, on the other hand, is not as firm when cold, but is also less heat sensitive. When it warms up, light memory foam doesn’t soften up as much as denser memory foam. This means that the firmness of a memory foam mattress can vary widely between brands. And a mattress can change firmness during the night as the bed becomes warmer. If you are considering a memory foam mattress, be aware that the level of firmness is hard to predict and will fluctuate during the night.

Hyper-Elastic Polymer™ Material

In contrast, the Purple® Mattress has a Hyper-Elastic Polymer™ material in the Purple Grid™ which does not retain heat. A Purple® Mattress has the same firmness when you wake up in the morning as it did when you went to bed.

Gel Memory Foam

Some manufacturers add gel to memory foam. The gel can help enhance support, but it is primarily used to cool the foam by absorbing and transferring heat. However, be aware that even gel-infused memory foam will heat up during the night.

Latex Foam

Latex mattresses were invented in the 1920s but did not become popular until after the introduction of memory foam mattresses in 1991. Latex foam is resilient. This means that the more your body weight pushes it down, the more it pushes back. Therefore, latex feels soft at first, then firmer as you go down until a balance is reached. Latex foam can be made softer or firmer in the foaming process. There are two primary processes for making latex foam. Dunlap latex is denser and firmer at the bottom, but less dense and softer at the top (unless flipped over). Talalay latex has the same density all the way through the mattress.

Coils (Springs)

The original support for modern mattresses was an array of steel coil springs known as innerspring. These coils were actually developed from springs in buggy seats. By World War II, almost all mattresses made and sold commercially were innerspring mattresses. There was little padding — typically just some cotton batting — so the firmness depended entirely on the coils.

The original springs were Bonnell coils, followed by pocket coils, offset coils, and continuous coils. Most of these coils are on the firm side. Continuous coils are generally the firmest, but extremely firm Bonnell coils are used for extra heavy people.

Today, pocket coils are the most popular type of innerspring, mostly because of their conformity and ability to minimize motion transfer. They are also the coils which do best for compressing and rolling a boxed bed. Hybrid mattresses, such as the New Purple® Mattress, use pocket coils and are quite popular these days.

Where do hybrid mattresses sit on the firmness scale?

Hybrid mattresses essentially replace the foam support core with pocketed coils. Mechanically, it may be the same firmness, but for a sleeper, this could feel a bit softer since the pocket coils are more conforming than a very firm foam slab.

Micro-Coils

Micro coils — including nano coils — are sometimes used inside innerspring mattresses. These are extremely short pocket coils. An array of micro-coils is made as a sheet (the fabric pockets adhere to each other). This sheet of tiny coils can be inserted between two foam layers to adjust the firmness of the mattress. The actual effectiveness in moderating firmness is debatable, but they do seem to help keep a mattress cooler.

Pillow Top

A pillow top mattress is not really a unique material, but rather an added section of a mattress. A pillow top mattress has a padded cover sewn to the top of the mattress to serve as a comfort layer. Most pillow tops are 1” to 1.5” high, though some are 2” or more. The materials in a pillow top can be made with fibers, poly foam, or memory foam.

A pillow top will make a mattress softer. The way the pillow top is attached to the mattress can affect how the mattress feels. The bottom cover of a traditional pillow top is sewn to the top panel of the mattress cover, and it is single edged like a true pillow. This makes it feel softer at the edges.

Body Weight

As a general rule, a heavier person needs a firmer mattress, while a lighter person will typically prefer a softer mattress. You need enough support to align your spine properly, and if you are too heavy for the mattress, it will sag. And if you are too light, you may not sink in enough for real pressure relief. Use the mattress firmness scale guide in this article to indicate the range of firmness appropriate for you. Your best mattress should be within this suggested range.

Body Size and Shape

Body type is an important factor when determining the firmness of a mattress. Some people are tall and lanky, while others are short and stocky. A compact body puts more concentrated pressure on a mattress. For example, press on your mattress with an open hand, then with a closed fist. Which sinks in more? This is why a stocky sleeper may need a slightly softer mattress to lessen pressure than a lanky sleeper with long arms and legs.

Sleeping Position

Interestingly, your sleeping position can also affect the firmness of a mattress. A sleeper is more likely to float on top of the mattress when sleeping with their arms and legs spread out, as opposed to sleeping curled up in a fetal position. Sleeping in a ball on a firmer mattress puts more pressure on protruding joints. If you or your partner tends to curl up at night, pick a mattress at the lower end of your firmness range.

There are three basic sleeping positions: back sleeping, stomach sleeping, and side sleeping (the fetal position is a variation of side sleeping). Each sleep position can affect the preferred level of firmness in order to promote proper spinal alignment.

The best sleeping positions are largely determined by health conditions and other factors. Side sleeping is better for sleepers with breathing problems, such as sleep apnea or asthma. Back sleeping is recommended for those who have had hip surgery, back surgery, or have scoliosis. The one significant benefit of stomach sleeping is the avoidance of snoring and sleep apnea, though you need proper support to avoid back and neck problems.

Supine Position

Sleeping on your back is known as the supine position. It is a natural position for the spine, but a certain amount of firmness is still needed to keep the lumbar from sagging. Typically, the recommended firmness for back sleepers is medium to medium firm (4-7). Even then, some back sleepers may need additional lumbar support, and it’s a good idea to lift the knees slightly with a pillow. Adjustable foundations, such as the Purple PowerBase, are better for back sleepers than for other sleep positions, especially if paired with a good mattress.

Side Sleepers

More people sleep on their sides than on their backs or stomachs. A side sleeper needs to have the shoulders and hips sink into the mattress. This reduces pressure on the joints, and it allows the spine to be laterally straight. For these reasons, a side sleeper should consider a mattress at the softer end of the preferred firmness range (4-5 for most).

Stomach Sleepers

Stomach sleeping is not as popular as side sleeping or back sleeping. These sleepers should choose a mattress on the firmer end of the preferred range (6.5-7). Even then, the pillows used by a stomach sleeper are very important. Many stomach sleepers use body pillows because they can help support the spine.

Health Conditions

Some health conditions necessitate having a softer or firmer mattress. For instance, some mattresses are designed with a combination of softness and supportive resilience for fibromyalgia, while other mattresses are developed to help acid reflux sufferers. Firmer mattresses are typically prescribed for people with back pain. However, the phrase, “The firmer, the better” is now shown to be an extreme view, since what is needed is underlying support with a softer surface. Many customers base their mattress ratings on how well the mattress relates to their specific health conditions.

Sleep Apnea
Sleep apnea is usually addressed either by an elevated upper body (with a wedge or an adjustable base) or by side sleeping, and side sleeping requires a softer mattress. If a person can’t breathe unless sleeping on their stomach, then they need a firmer mattress and added support for the belly/lumbar.

Sciatica
Sciatic nerve pain requires a softer mattress for less pressure on the nerve. Sufferers of sciatica are also often advised to sleep on the side opposite of the side with the pain, again calling for a softer mattress.

Scoliosis
People suffering from a curvature of the spine should sleep in the supine position. The mattress should be medium firm to firm, since sagging will make the problem worse.

Partner Sleeping

If you share a bed with someone else, chances are that each of you prefers a different level of firmness. According to mattress reviews, the best mattress for couples is typically a king mattress which can adapt itself to each of you.

The best solution is a medium-firm mattress with a softer top layer over a supportive and resilient layer, such as the Original Purple® Bed or the New Purple® Mattress. You can also put two twin XL mattresses side by side to make a king bed. This way, one mattress could be quite soft while the other is extra firm.

The Mattress Firmness Scale

The mattress firmness scale defines how firm or soft a mattress feels, both for the comfort layer and for overall mattress support. This is done in two ways. One method uses descriptive words for each level of firmness. The other way is to assign a numeric value (usually 1 to 10), which may be refined to include decimal numbers (such as 4.5 and 6.7) or fractional numbers (5½, 6½).

Terms

Not everyone is consistent in how they describe mattress firmness. Sometimes, the words “plush” or “immersive” is used to describe the softness of a mattress. On the other end of the scale, most brands use the term “firm mattress,” although some people may say “hard mattress.”

The Numeric Firmness Scale

When choosing a mattress, it’s important to know what the description means if it has a numeric firmness rating. Manufacturers, retailers, and reviewers often assign a number on a 10-point scale to rate the firmness of a mattress. Most websites, including Consumer Reports, assign a 10 to the firmest mattresses. However, a few brands use 10 for the softest mattresses, and 1 for the firmest. Admittedly, this can certainly be confusing! Is anyone for standardization?

How Is Mattress Firmness Measured?

The firmness of a mattress can actually be measured scientifically. A standardized weight with a defined surface area is pressed into the mattress. This can be an object with a standard shape, such as a ball or a cube, or it could be a plate mounted to a mechanical arm. The amount of sinkage (how far it goes into the mattress) is measured for each weight and amount of pressure. This is how many mattress companies rate the firmness of their mattresses.

A mattress is considered soft (plush) if it sinks in between 1.5 and 3 inches. If the sinkage is just an inch, it is medium. If there is little sinkage, it is firm. A mattress is labeled as extra firm if there is no sinkage at all.

However, for human sleepers, there is more involved than simple mechanical firmness. Also, the effective firmness of a mattress — how it feels to you — depends on the mattress type. This is why there is always a variance in how firm a mattress is to the user. Keep this in mind as we discuss the firmness levels.

Firmness Levels

Let’s talk about the seven firmness levels: Extra Soft, Soft, Medium, Medium-Firm, Firm, Extra Firm, and Universal.

Extra Soft: 1-2

These are the softest mattresses. Extra Soft is rated 1-2 on the numeric scale. It’s extremely rare to sleep on a mattress rated at 1.0 because it has practically zero support. Most extra soft mattresses are rated at 2 and are generally quite deep. They are very soft at the top with many layers beneath. The layers become firmer as they go down. This is the only way an extra soft mattress can have adequate support.

Extra soft mattresses are sometimes considered luxury mattresses because you can sink in deeply and still find support and comfort. The extra layers make the mattress very expensive and very heavy and may be too high off the ground for many sleepers. Believe it or not, some companies sell bedroom steps made for getting in and out of very high luxury beds.

Soft: 3-4

A soft mattress is usually rated 3-4. This is a bit too soft for average-size sleepers, and especially for heavier sleepers because they sink in too much. Very lightweight (110 lbs. or less) and lightweight adults may sleep well on a soft mattress. The best position for a soft mattress is side sleeping because it allows the shoulders to sink in, relieving pressure on the joints. A lightweight side-sleeper can still have proper spinal support, but heavier side-sleepers need more lumbar support.

The best soft mattress is typically rated at 4 since it provides a little more support. This is especially true if there is a transitional layer from the soft top layer to the base. This keeps the softness of the top while providing needed support. The Purple® 4 is considered by many to be the best plush mattress, because of the underlying conforming support. Some call it the best mattress for side sleepers.

Small children still using crib or toddler size mattresses can be adequately supported by a soft mattress rated 3 because they are extremely lightweight and don’t sink in very much.

Medium: 4-5

The average numeric rating for Medium is 4-5. This is in the middle range, which is the firmness preferred by many. In fact, most mattresses sold are either Medium or Medium Firm.

A medium mattress is a good choice for average-size side sleepers and back sleepers. Stomach sleepers do better with Medium Firm or Firm because more mattress support is needed to keep the spine from sagging.

Innerspring mattresses with four inches of latex foam or memory foam comfort layers are usually rated as Medium. With about three inches of foam, they may be rated as Medium Firm. Of course, this depends on the firmness of both the coils and the foam.

The Purple® 3 is a top medium-firm mattress.

Medium-Firm: 6-7

Medium Firm (6 to 7) is, for most people, the firmness level of the most comfortable mattress. While it’s not suitable for everyone, it does suit the largest number of people. This firmness is right for all sleeping positions of average-sized sleepers, and acceptable for lightweight and light heavyweight sleepers.

The best medium-firm mattress has enough softness on top to ease pressure on larger body parts, such as shoulders and hips, and enough support for the head, spine, and feet. This is especially important for side sleepers since more people sleep on their sides than on their backs or stomachs.

A Medium Firm mattress has layered support: a softer top layer, a firmer transition layer of high-density foam, and an extra firm base. This graduated support is in the Original Purple® Bed. The New Purple® Mattress (Purple 2, Purple 3, and Purple 4) does this with its pocketed coil support core. The Purple® 2 is Medium Firm or Firm, but with a soft touch on top.

Firm: 7-8

Firm mattresses are rated between 7-8 on the scale. Some people — especially heavier people — prefer a firmer feel in a mattress. The best firm mattress has a medium or medium-firm top layer to provide some pressure relief. The transition layer is firm, and the base is extra firm. A firm mattress may be preferred by some average-sized stomach sleepers since it has more support.

Firm Memory Foam Mattresses
A firm memory foam mattress can provide more pressure relief because the memory foam is denser, and therefore more heat sensitive. However, this also means more heat retention. And sleepers can have more difficulty changing their sleep position or getting in and out of bed.

Firm Innerspring Mattresses
Innerspring mattresses have been known for their firmness, especially the original innersprings known as Bonnell coils. Pocket coils (also called Marshall Coils after their inventor) were patented in 1900 and tended to be not quite as firm as the Bonnells. Pocket coils are usually rated Medium Firm or sometimes on the lower end of Firm (6.5-7) because they were designed to be conforming for pressure relief.

In 1926, Frank Karr patented offset coils which were firmer but had a bit more give than Bonnells. A few decades later, Serta developed continuous coils, which are more durable than other innersprings and rated on the high end of Firm.

Today’s innerspring mattresses are not as firm as they were in the past. At the same time, they are not as durable. The springs are often made with lighter wire which reduces firmness but also makes them wear out faster. The springs may last a long time, but the foam can break down — especially memory foam. The resulting sag is the most common complaint about traditional innerspring mattresses with foam comfort layers.

Extra Firm: 9-10

Extra firm mattresses are for sleepers who are very heavy or have specific health issues, such as sciatica. Several mattress brands have Extra Firm models designed for these sleepers. One example is the GrandBed by Tempur-Pedic, which was sold for many years before being discontinued in mid-2019.

Some mattress owners who feel their mattresses are too soft will often get an Extra Firm mattress topper. That sounds nice, but the softer material under the topper can create some sagging. However, an Extra Firm topper can actually soften an Extra Firm mattress by simply adding more material, which allows more immersion.

Universal

The Universal rating is different than the other firmness ratings. A mattress can be considered to be Universal if it is comfortable for most people and fits a wider range of firmness preferences. A mattress which has “Universal Firmness” is therefore usually Medium to Medium Firm (4-7).

However, there is another connotation to “universal.” Couples are usually of different builds and sizes, so for a mattress to have a universal feel, it has to suit two sleepers with notable differences in body build, size, and weight. This means that it should have both conformity and resilience.

This is accomplished by having a conforming layer and a resilient layer which work together. For example, in the Purple® Mattress, the Hyper-Elastic Polymer™ material in the Purple Grid™ is highly conforming, more so for the lighter person. The underlying transition layer of high-density polyurethane foam (as firm at 1.8 lbs/ft³ as the base in most memory foam mattresses) — or the layer of pocketed coils in the New Purple® Mattress — has enough resilience to keep the heavier person from sinking too far.

Several other mattress brands balance the conformity of memory foam with a layer of latex or latex-like foam. Latex foam is resilient. Even if it gives, it still pushes up, and the deeper the body sinks in, the more the push increases. Memory foam, on the other hand, softens with body heat until a balance is reached, and it cradles the sleeper without pushing back.

Adjusting Firmness

Sometimes a mattress feels too firm or too soft. A few mattresses can be opened, and the foam layer changed or flipped. The most common solution is using a mattress topper. This is an easy way to make the mattress feel softer since most mattress toppers are designed for this, but an extra firm topper can help increase firmness. Memory foam and polyurethane foam are the two most common ingredients in mattress toppers. Other ingredients are cotton or wool batting, polyester fibers, and down. A few high-priced ones use horsehair. Although it softens the mattress, a topper does take away from the benefits of the top comfort layer, which in Purple’s case is the Smart Comfort Grid™.

How to Test the Firmness of a Mattress

When shopping for mattresses online, one issue is that we want to lay on the mattress and feel the firmness level for ourselves. Fortunately, some online brands, such as Purple, are also available in select retail stores. You can walk into a local store, test the mattress, and then have it delivered to your home or pick it up at the store.

Let’s say you are in a store looking at a mattress. How do you test its firmness? Simply put, it’s as easy as PPL — Punch it, Push on it, and Lie on it.

Punch It

Some customers like to hit the surface of a mattress with their hands to see how much bounce it has. Punch the mattress and see how far in your hand goes. For a consistent firmness measure, just be sure to punch each mattress the same way.

Push on It

Push hard on the mattress, putting all your weight on your hand. Try it with an open hand and then with a closed fist. See how far your hand sinks into the mattress. Like the punching test, this method is not very scientific — it tells you more about the surface of the mattress than it does about what is farther down.

Lie on It

This is a better test than punching or pushing. After all, it’s what you’ll be doing with the mattress if you buy it. Almost all mattress stores and showrooms let customers lie on the mattresses to get the feel of the comfort and firmness levels.

Most shoppers will lie on mattresses for ten minutes or less. Some stores encourage you to lie on a memory foam mattress for half an hour or more since this gives the memory foam time to adjust to your body size, shape, weight, and temperature. It also allows time for your body to adjust to the mattress. 10 minutes is not enough time to sense a problem you may have with the mattress, which is true for any type of mattress, not just memory foam.

Test at Home

You can also test the mattress at home. Some mattress companies offer a sleep trial, so you have plenty of time to test your mattress. With Purple’s 100-Night Trial, you can try the Purple® Mattress for 100 nights! If it is not a good fit, return it and get a full refund.

How can I tell if my mattress is too soft or too firm?

If a side sleeper wakes up with sore hips, shoulders, and knees, then the mattress is too firm. On the other hand, if a side sleeper wakes up with a sore back, then the mattress is probably too soft. Similarly, when a back sleeper wakes up with a sore back, it’s a sign that the mattress is not firm enough.

How Firm Is the Purple® Mattress?

Professional reviewers who have tested the Purple® Bed variously rate it as 6.0, 6.5, 6.7, and similar points within the Medium Firm range. Because of Purple’s Hyper-Elastic Polymer™ material and the design of the patented Purple Grid™, Purple mattresses are rated as a Universal Firmness mattress. This includes both the Original Purple® Bed and the New Purple® Mattress. The walls of the cells in the Purple Grid™ collapse in proportion to the weight and shape of the sleeper’s body. This helps it conform to a variety of body types and sleeping positions without the heat build-up of memory foam. When weight is lifted, the cell wall returns to its original height.

While the Original Purple® Bed is rated as Medium Firm, the three variations of the New Purple® Mattress vary in firmness. The Purple® 2 is Medium Firm and has a 2-inch Purple Grid™. The Purple® 3 is considered Medium and has 3 inches of the Hyper-Elastic Polymer™ material. The Purple® 4 is rated Medium Soft and comes with a 4-inch Purple Grid™.

Purple mattresses are suitable for all sleeping positions — even stomach sleepers. Since it is so conforming, the mattress continues to support the lower spine.

For most couples, this means that two people with different weights and sizes can be comfortable in the same bed at the same time. Part of this comfort comes from minimized motion transfer. When one partner climbs in and out of bed, it should not wake the other sleeper.

Mattress Firmness Guide

Whether you prefer a mattress that’s firm or soft, the Original Purple® Bed and the New Purple® Mattress are designed to meet most considerations. The three levels of the New Purple® Mattress (Purple 2, Purple 3, Purple 4) give you even more choice in mattress firmness. If your bed will be shared with a partner, look for a mattress that suits you both. Purple mattresses are crafted for Universal Firmness and should accommodate both of you.

As you shop for a new mattress, it’s important to consider the level of firmness as well as the type of mattress. Decide which firmness level is best for you according to your body size, weight, sleeping position, and any special needs you may have. It can make the difference between a good night’s sleep and a great night’s sleep.

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