Mattress Firmness Guide

October 09, 2023 7 min read

One of the most important factors to consider when choosing a mattress is firmness. Although firmness is a term that is used in the mattress industry, there is very little information available that explains what firmness is and why it is so important.

This guide seeks to understand better mattress firmness and how it affects other essential sleep factors such as comfort and support. Issues such as temperature, motion transfer, and of course sex, are also discussed. Plus, we provide vital information on choosing just the right firmness to meet your personal preferences relative to additional factors such as your weight and sleeping position. We aim to offer you an expert explanation of mattress firmness to arm you with the knowledge to make the best choice to improve your quality of sleep.

What Is Mattress Firmness?

Firmness describes how a mattress feels in terms of comfort. Sleeping on a hard surface (like the floor) can be described as one extreme of firmness while floating on a cloud, the other extreme. The measure of firmness is also highly subjective. What feels comfortable to one individual may be very uncomfortable for another person. Mattresses come in so many different varieties of firmness to suit the varying needs of every type of customer.

Does Firmness Mean The Same as Support?

It is crucial to understand that firmness does not mean the same as support. Support is about how well a mattress can promote the alignment of the spine. Firmness refers to comfort and how hard or soft the mattress feels. While there is a relationship between firmness and support, it is best to consider these two factors separately when choosing a mattress. A mattress that offers features such as pressure relief and proper spinal positioning will offer support regardless of how soft or hard it is. A firm mattress, on the other hand, does not necessarily offer better support. Firmness can be subjective, whereas support cannot.

The Firmness Scale

Terms such as firm, extra-firm, medium-firm, or plush describe mattress firmness. However, different manufacturers may apply these terms differently and can make it challenging to compare mattress models across the board. The mattress scale is, therefore, a far better way of rating firmness from 1-10 as described below:

1 – Extremely Soft – Maximum softness with plenty of giving or sink. It is rare to find a mattress that is rated one on the firmness scale.

2 to 3 – Soft – Soft with some give or sink.

4 to 6 – Medium – Average firmness with limited give or sink and moderate plushness.

7 to 9 – Firm – Harder mattress with little give or sink and limited softness.

10 – Extremely Firm – Refers to a hard mattress with no plushness, softness, or sink. It is rare to find an extremely firm mattress.

The Firmness Scale In-Depth

This section provides greater detail about the firmness scale. It also gives insight into how the different levels of firmness affect the amount of support relative to the sleeping position that is best suited to each:

Soft (Level 1 to 3)

A level 1 mattress is rare, and you are more likely to find level 2 and 3 mattresses on the firmness scale.

Support – The softness of these mattresses allows them to mold to the body’s shape, thereby relieving pressure on specific points and offering better spinal alignment. However, the sink or give of the mattress is also greater, resulting in curvature of the spine and uncomfortable for most people.

Sleeping Position – Soft mattresses are a perfect fit for a side sleeping position. Pressure tends to be more pronounced on the hips and shoulders of side sleepers who can benefit from more cushioning at these points. The lack of firmness can result in misalignment of the spine. This is so for those who prefer to sleep on their back. Likewise, those who sleep on their stomach can suffer spine misalignment because there is too much sink.

Medium (Level 4-6)

Support – These mattresses generally offer the best of both worlds with good overall support and good contouring to relieve pressure while limiting excessive sinking into the mattress. The medium-firm mattress maintains good spinal alignment for most people.

Sleeping Position – The mattress is suitable for sleepers in most positions and is the ideal solution for combination sleepers who sleep in more than one position. It is also a good choice for couples who don’t necessarily sleep in the same position.

Firm (Level 7-10)

Support – While firmer mattresses don’t have the molding properties of a softer mattress option, they can still offer sufficient support with some cushioning to relieve pressure on certain points.

Sleeping Position – This is not ideal for side sleepers who may have difficulty with the lack of sink and, therefore, pressure point relief. Back and stomach sleepers may find this mattress prevents the lower back or tummy from sinking into the mattress. These are the firmest mattresses available on the market but are generally uncomfortable for sleepers in most positions.

Why Is Mattress Firmness Important?

Most people accept the importance of firmness as a primary consideration when choosing a mattress without really understanding why it is important. This section delves deeper into the reasons why firmness is such a vital factor to consider:


The importance of comfort is easily understated. A cozy mattress is inviting and plays a significant role in the ability to sleep well. If you can’t get comfortable when you get into bed, then it is unlikely that you will get a good night’s rest. In addition, a comforting mattress will contribute to your overall quality of sleep. The experts recommend a sleeping environment and bedtime routine that creates a sense of calm and relaxation. A comfortable mattress can go a long way towards making this ideal sleep environment.

Comfort is also essential to avoid waking up with aches and pains. If you are tossing and turning, trying to get comfortable, it is only to be expected that you will feel the effects of your contortions the following day. Plus, an uncomfortable mattress is probably not providing you with the support you need, increasing the risk of chronic neck, shoulder, and back pain when you get out of bed in the morning.

Finding Your Optimal Firmness Level

Now that you have a better understanding of mattress firmness, and with this in mind, we can determine which level of firmness will best suit your unique needs. There are several factors that you need to consider when making a decision.


The first and perhaps most crucial factor to consider is your perception of what is comfortable. Remember that every person may experience comfort differently and what feels significant to one person may be uncomfortable for another.

Start by thinking about the mattress you are currently sleeping on. What is its firmness level, and would you prefer a mattress that is slightly softer or firmer? Did you prefer that mattress to your own? Also, consider your comfort sleeping on other beds, such as in a hotel or while visiting friends or family. It isn’t necessary to know the exact firmness level of a different mattress to understand better whether your personal preferences lean towards a soft, medium, or firm mattress. This is especially significant if you prefer sleeping on a highly plush or very hard mattress.

While we have provided some general guidance regarding the level of firmness relative to the most suitable sleeping position, it is best to consider your own experiences. If you know what firmness level is more comfortable for you, go with it no matter what firmness the experts say will be better.


A mattress reacts to the amount of weight and pressure that it exerts on it. Weight can therefore influence how a specific person perceives firmness.

Sleepers weighing under 130 pounds most often find softer mattresses that are lower on the firmness scale more comfortable. Lighter-weight people may find that a firmer mattress does not give them the contouring they need to be comfortable and may offer less pressure point relief. A mattress in the range of 2 to 5 on the firmness scale is a good choice.

Sleepers weighing between 130 and 230 pounds commonly find a medium-firm mattress that offers them greater comfort. A mattress in the range of 4 to 6 on the firmness scale provides sufficient cushioning while not compromising on the support that the mattress has to offer.

Sleepers over 230 pounds may prefer a mattress on the higher end of the firmness scale – between 6 and 8. Greater weight means greater pressure on the mattress. A soft or medium-firm mattress may offer too much give, causing the sleeper to sink into the bed too much. Remember that a firm mattress doesn’t necessarily have to be hard to offer cushioning.

Sleeping Position

Your preferred sleeping position also dictates your choice of a mattress. Side sleepers have more significant pressure on the hips and shoulders.  For this reason, a softer mattress is a good choice to compensate and cushion these points. It also keeps the spine aligned. Therefore, a soft to medium-firm mattress suits people who sleep on their side—such mattress range of 3 to 7 on the firmness scale.

Back sleepers are at an advantage because this position is naturally good for spinal alignment. However, they do require additional support in the lumbar region (lower back) to prevent exaggerated curvature in any direction. A firmer mattress in the range of 4 to 7 is an excellent choice for back sleepers.

Stomach sleepers need to avoid soft mattresses that sink a lot. The pelvic area and abdomen sink more than other body parts creating a “U” shape while sleeping, which is an unhealthy curve for the spine. A firmer mattress in the range of 4 to 7 is recommended for stomach sleepers to ensure sufficient support for the spine

Combination sleepers are people who sleep in 2 or more different positions – either turning over during the night or sleeping in various positions on consecutive nights. A medium-firm mattress within the range of 4 to 6 is advisable for these sleepers. It provides the most excellent flexibility and balance between comfort and support across all the different sleeping positions.