Understanding the Mattress Firmness Scale For Your Body Type and Sleep Position

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Written by: Alex Savy
Last updated on

Mattresses come in various firmness levels ranging from very soft at 1 to extremely hard at 10, with 5 considered a medium firmness level. Finding your ideal mattress firmness level depends a lot on your preferred sleeping position, body type, and body weight. People typically make the mistake of choosing a mattress that is too soft for their bodies resulting in aches and pains when they wake up. This article will help you choose the right mattress firmness that suits your needs and ensures you wake up feeling refreshed and energetic every day.

Key Takeaways

  • A medium-firm mattress is the most popular mattress firmness level because it supports more sleeping positions and promotes the spine’s natural curvature.
  • Mattress materials like latex, memory foam, and pocketed coils make a mattress feel firmer and more comfortable, while also encouraging better sleep.

What is the Mattress Firmness Scale?

The mattress firmness scale is a measurement from 1-10 that indicates how soft or hard your mattress is. A measurement of 1 would be extremely soft and would compress easily when pressure is applied to a mattress surface. Conversely, a measurement of 10 would be extra firm and would barely compress when pressure is applied to the mattress surface.

Other mattress firmness measurements would fall between these two soft and hard extremes, with a measurement of 5 considered to be medium firmness. Medium-firm mattresses would fall on the firmness scale at around 6 or 7 and are the most popular mattress firmness levels among sleepers because of the support that they offer the spine’s natural curvature (1). Mattress firmnesses of 4 and 3 are soft and plusher but don’t support the joints and spine enough, especially for side and stomach sleepers.

Mattress firmness scale
Mattress firmness scale

Types Of Mattress Firmness Levels

Mattress firmness levels are measured according to the amount of sinkage and resilience the mattresses offer when pressure is exerted on the sleeping surface. The different types of mattress firmness levels range from 1-10—with 1 being extra soft, 10 being extra firm, and 5 as medium, with the other numbers indicating firmness or softness graded along this scale.

Soft Mattresses 

Children and people who have lighter weights can use soft mattresses because their body weights won't make the mattress compress too much. Soft mattresses have a firmness level of 1-2, making them conform more closely to the body. Some back sleepers enjoy sleeping on a soft mattress because it sinks in more than other firmness levels and can create the feeling of being enveloped and caressed.

Because softer mattresses tend to weigh less than denser mattresses, you might find that it shifts in the bed over the course of time. We recommend anchoring the mattress to the bed with mattress stabilizers or tape to prevent the mattress from sliding around the bed frame.

Medium-Soft Mattresses 

Medium-soft mattresses can be slightly better than extremely soft mattresses because they offer a little more support and buoyancy. Children between the ages of 3-10, or who weigh less than 130 pounds will probably find a medium-soft mattress comfortable enough to support their growing bodies (2).

Medium-soft mattresses have a firmness level of 3-4. When looking for the best soft mattress in Canada, for instance, you’ll want to select the mattress based on its materials and the weight of the person using the mattress to ensure optional comfort.

Medium Mattresses 

Teenagers and pre-teens, as well as people who weigh between 130-210 pounds, will find that a medium mattress is soft enough to cradle and support them because it has a firmness level of 5. People who adopt many different sleep positions during the night might enjoy a medium mattress because it offers the softness that side sleepers enjoy and the firmness that back slippers prefer.

Medium-Firm Mattresses

Medium-firm mattresses are the most popular ones among customers because they offer the best support to the spine and joints while feeling extremely comfortable. A medium-firm mattress resists excessive sinkage, which can cause extreme curvature of the spine resulting in back pain and poor posture. If you’re looking for the best mattresses for back pain, check the advertised firmness level is either a 6 or 7 so that it supports the entire body and reduces pressure points.

A medium-firm mattress comprises many layers in its construction. Each layer plays a vital role in creating a sleep surface that is resistant to pressure while contouring the joints and spine. The base layers are the denser layers that provide support, while the inner layers work together to make the sleeper feel as if they are suspended in a cloud. The outer layers, closet to the surface, are the cushioning and comfort layers that give a medium-firm mattress its plush feeling. 

A medium-firm mattress on a bed frame
A medium-firm mattress on a bed frame

Firm Mattresses

A firm mattress doesn’t sink in as much as other mattresses because its layers are more resilient and buoyant. Firm mattresses are ideal for people who weigh more than 230 pounds, while people who weigh more than 400 pounds might be better off with an extra firm mattress because its layers will be better able to withstand the compression from heavier weights.

Firm mattresses are often made with high-density foam that is resistant to excessive pressure. But this can sometimes mean that the mattress doesn’t respond as fast to the body and doesn't allow the body to sink into the mattress. Some people find that a firm mattress doesn’t feel as snuggly or contouring when laying on their sides or back because its firmness doesn’t have any give. But people who prefer sleeping on their stomachs often find that a firm mattress provides the ideal amount of resistance this position requires.

What is the Most Popular Mattress Firmness Level?

The most popular mattress firmness level is a medium-firm mattress with a measurement of around 6-7 on the firmness scale (3). A medium-firm mattress is responsive and contouring, allowing it to perfectly cradle the hips, shoulders, and spine when sleeping. A medium-frim mattress is also accommodating for sleepers who enjoy varying their sleeping positions during the night because it offers sufficient resistance for stomach sleepers as well as back sleepers.

What Mattress Firmness Best Suits Each Sleeping Position?

Medium and medium-firm mattresses are ideal for side sleepers because they contour around the hips and shoulders and provide excellent support to the spine. Firm mattress suit people who enjoy sleeping on their stomachs because the mattress’s firm layer prevents over-extension in the spine, which can lead to posture and spine health issues. Finally, soft mattresses don’t offer enough support to a resting body but may be the right choice for lightweight people who sleep on their backs.

Mattress Firmness LevelSide SleepingBack Sleeping PositionStomach Sleeping
SoftLess supportLess supportNot recommended
Medium-SoftGood supportGood supportNot recommended
MediumBest supportGood supportLess support
Medium-FirmBest supportLess supportGood support
FirmNot recommendedNot recommendedBest support

How to Determine Your Mattress’s Firmness

Mattress firmness is subjective. So even if the mattress manufacturer lists a particular mattress as firm or soft, your experience and preference may differ from their categorization. Review articles that thoroughly examine, for instance, the best firm mattresses in Canada, and explain their measurement criteria can help you choose the ideal mattress firmness for your needs.

Pro Tip: You can also test the mattress yourself by laying on it or pressing down on it with your hand. A soft mattress will offer less resistance and allow your hand or lying body to sink into the mattress more easily, while a firm mattress will offer more resistance and feel more buoyant when you lay on it.

Testing a mattress's firmness
Testing a mattress's firmness

Mattress Materials that Influence Firmness

The materials and manufacturing processes used when constructing a mattress significantly affect a mattress’s firmness level. Resilient and dense materials will make a mattress feel firmer because the layers will withstand compression better. Conversely, supple and yielding materials will make a mattress feel softer as the layers compact under the weight of a sleeping person. Some of the materials that are used to produce a mattress include polyfoam, memory foam, latex, fiber, and pocketed coils. 


Polyfoam is a synthetic foam material that is made from petroleum products. It is lightweight, as well as cost-effective, and easy to produce, which is why it is used in most mattresses. Polyfoam can be produced in various densities, which determine the firmness of the mattress—with high-density foam being the firmest and low-density foam the softest. 

Memory Foam

Memory foam is more elastic and viscous than regular foam and contours to the body so that you feel cradled when sleeping. Memory foam responds to pressure exerted on the surface and retains heat which also assists with its ability to cushion aching joints snuggly.

Memory foam comes in various densities and compositions, like gel-infused, open pocket cells, and plant-based versions. These newer memory foam compounds help the foam dissipate heat so that sleepers don’t feel sweaty and clammy during the night. Some of the best memory foam mattresses in Canada, for instance, have various layers of these different foams that make the mattresses more comfortable and customizable. 

A memory foam mattress on a bed frame
A memory foam mattress on a bed frame


Latex is a natural material produced from rubber tree sap. It is one of the most resilient mattress materials used in modern mattresses—making it supremely responsive and buoyant. Latex is a naturally cool material that prevents overheating when sleeping by drawing the heat away from the body. Many mattresses, like this reviewed Douglas mattress, use materials that mimic latex’s supportive properties without the hefty price tag, meaning you can get the benefits of sleeping on latex at a fraction of the cost. 


Fiber can be synthetic or natural and is the material that gives a mattress its plushness. The filling inside pillowtop mattresses and the outer cushioning layers is usually a combination of various types of fiber materials that are adjusted to give the mattress a firmer or softer feel. But fiber can only marginally improve a mattress's softness and doesn’t contribute to a mattress's responsiveness because it doesn’t adapt to the body or spring back to its original shape as memory foam does. 


Traditional mattresses were made with coils, also known as innerspring mattresses. Some people prefer coil mattresses because they are typically bouncier than other mattresses, meaning sleepers often experience rocking and rolling motions whenever they change sleeping positions or a partner gets into or out of bed. Coil mattresses are quite firm because the metal springs resist pressure.

Coil mattresses can cause a lot of sleep disturbances because they creak, are very bouncy, and don’t contour the body to prevent pressure points. This is why many manufacturers incorporated memory foam and latex layers into the mattress designs and included the coils as the bottom layers. These are called hybrid mattresses and are among the  best mattresses in a box you’ll find in Canada. Mattresses that are made with a coil base and foam layers offer sleepers the best of both worlds—now they can have the buoyancy of coils with the firm support of foam and latex.

Factors that Influence What Mattress Firmness To Choose

When choosing a mattress firmness level, you should consider important aspects like who will be sleeping on the mattress most often as well as the environment the mattress will be in. It is also important to take a look at the mattress materials to determine if they will offer the right type of firmness you desire. If you are looking for a mattress with a firmness level that will effectively reduce aches and pains, then you should choose a mattress with high-quality materials and multiple layers that support the body. 

Individual Body Weight

A who weighs less than 100 pounds will typically sleep well on a soft or medium soft mattress, provided they don’t have health or orthopedic issues. While people who weigh 105-125 pounds will feel comfortable on a medium-soft mattress.

The general rule is that the heavier a person is, the firmer their mattress should be so that it can properly support their body and keep the spine in a neutral position no matter what sleeping position they prefer.

People who weigh between 130-230 pounds often find that a medium-firm mattress offers adequate support when sleeping. This is because mattresses with a medium-firm feel can typically support two people—one on each side of the mattress—who each weigh 230 pounds or less. This means that a medium-firm mattress can fit a total combined weight of up to 460 pounds. Though if you weigh more than 230 pounds, you should probably consider getting a slightly firmer mattress. 

Room Temperature

Mattress materials are affected by temperature, particularly mattresses made from foams like memory foam and latex. These mattresses are produced to respond to body temperatures which is why they are so comfortable. But this also means that the mattresses are affected by major temperature fluctuations in the room. For instance, a warm room will make a mattress feel less firm, and a cool room will make the mattress feel less soft.

If you live in a climate that has warm temperatures throughout the year, then it might be a good idea to buy a slightly firmer mattress because the heat will cause the inner materials to become more supple. Alternatively, you can turn the thermostat to a cooler temperature which will help your mattress firm up a little.

Pro Tip: Turn your thermostat to a warmer temperature to make your mattress feel softer, or a cooler temperature to make it feel firmer. 

Mattress Durability

High-quality materials like latex, high-density foam, and pocketed coils make a mattress firmer and more durable. This is because these materials are more robust and can withstand extended periods of use—which is important because you sleep on your mattress every night and want it to last for several years.

The mattress’s construction and design also play significant roles when it comes to durability and firmness. Mattresses with reinforced edges, sturdy base layers, and more integrated layers will feel firmer and be able to endure everyday wear and tear.


The variety of mattresses available means that you can easily find a mattress at different price points along the mattress firmness scale. But if you want the firmness level you choose to maintain its support, bounce rate, and responsiveness, then you will find that mattresses made with high-quality materials like latex, and gel-infused memory foam will cost a little more.

Price doesn’t directly correlate to a mattress’s firmness level, but it does play a major factor in the mattress construction and materials, which will determine whether the mattress's firmness remains consistent over time. 

Sharing a Bed With a Partner

Couples who sleep in the same bed can have different firmness preferences based on their sleeping positions or weight. Because mattresses generally don’t come with different firmness levels on each side, couples usually have to make concessions and choose a mattress that fits somewhere in the middle in terms of firmness. Their best bet is usually a medium-firm mattress which supports more sleeping positions than other mattresses. 

Side sleeping is the most popular position, especially for people sharing beds with partners because it reduces snoring and sleep disturbance.  Medium-firm mattresses are one of the best mattresses for side sleepers because they keep the spine perfectly supported when sleeping, and reduce snoring and sleep apnea.

Mattresses For Pain Relief

A mattress with adequate firmness and support, while also cushioning the joints, can help reduce back, shoulder, and hip pain. A firm or medium-firm mattress allows the hip and shoulder joints to sing into the mattress surface so that they feel caressed and soothed. And when you factor in the gel-infused or cooling layers that are incorporated into high-end mattresses, the joints feel even better.

As the shoulder and hips are contoured by the mattress, the spine assumes a comfortable neutral position that eliminates back pain and posture problems. A medium-firm mattress has the right amount of resistance and buoyancy to fully support the musculoskeletal system and encourage deep rejuvenating sleep.

My Experience With Choosing the Right Mattress Firmness

I found that a medium-firm mattress provided the correct amount of contouring for my joints and back and that I felt suspended as the mattress’s buoyancy supported my full body weight. My experience when sharing a bed with my partner is that a medium-firm mattress suits both our sleep preferences because I enjoy sleeping on my side, and my partner prefers the back sleeping position. We also enjoy the motion isolation features inherent in the memory foam layers, which reduce sleep disturbances.


Is It Better To Sleep On a Firm Mattress or a Soft Mattress?

It is better to sleep on a slightly firmer mattress that has a plush cushioning top layer. This will allow your spine to remain neutral and relieve pressure on your joints. A firm mattress also makes getting into and out of bed easier.

What Mattress Firmness Is Better For Side Sleepers?

A medium-firm mattress is best for side sleepers because it cradles the hip and shoulder joints. It also offers adequate resistance for changing sleep positions from one side to another during the night.

How Do I Know If My Mattress Is Too Firm?

If you lay on your back and have a gap between the curve of your lower spine and the mattress, that you can easily slip your hand through, then your mattress is too firm and won’t provide support to your spine.


Knowing how to use the mattress firmness scale can help you determine how firm or soft your mattress is so that you get the best support when sleeping. A firm mattress is ideal for people who weigh more than 400 pounds and those who sleep on their stomachs most of the time. A soft mattress is good for people who weigh less than 110 pounds and enjoy sleeping on their backs. A medium-firm mattress is the most popular mattress firmness level because it accommodates more sleeping positions and suits most average-weight sleepers.

Still have questions about understanding the mattress firmness scale for your body type and sleep position? Alex Savy, the Co-Founder and Chief Editor at Comfynorth has reviewed countless sleep products with over 4 years in the industry and can help you find what you’re looking for. Reach out through email at [email protected]. When emailing Alex, include your full name and phone number or email address.


  1. Hong TT-H, Wang Y, Wong DW-C, Zhang G, Tan Q, Chen TL-W, Zhang M. (July 8. 2022). The Influence of Mattress Stiffness on Spinal Curvature and Intervertebral Disc Stress—An Experimental and Computational Study. Biology. 2022; 11(7):1030. Retrieved from:
  2. Na Yu, Chong Yu, Hui Li, Ming Li (May 2021). Effects of mattress firmness on body pressure distribution. Retrieved from:
  3. Duo Wai-Chi WonG, Yan Wang, Jin Lin, Qitao Tan, Tony Lin-Wei Chen, and Ming Zhang (January 25, 2019). Sleeping mattress determinants and evaluation: a biomechanical review and critique.  Retrieved from:

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