Learn more about mattress thickness to make the right choice.
When buying a mattress, it’s important to consider its thickness. This depends on various factors, such as age, weight, materials, and so on . Thickness affects not only the mattress’s comfort but also its durability. However, it’s not the only factor to consider, and it’s not always an indicator of quality.
First and foremost, it’s important not to confuse thickness with density. While mattress thickness and density are often perceived as related, they are in fact two distinct factors. A mattress’s density is the measure that corresponds to its firmness. Measured in kg/m³, a good mattress density is one that provides adequate support. We’ll explain in more detail below which density to choose (based on the different materials).
Learn more about mattress thickness in this article.
THE DIFFERENT MATTRESS THICKNESSES
A. Mattresses that are 15 cm or less in height
Mattresses that are 15 cm thick or less are primarily intended for children. Since children have different needs, a mattress that is only 15 cm thick or less provides them with excellent support.
However, adults should avoid this type of mattress, as it may provide insufficient support and could lead to back pain. They are generally considered low-end mattresses when it comes to adult mattresses and can be used as futons, for example.
B. A thickness between 15 and 20 cm
Between 15 and 20 cm thick, these mattresses are generally considered entry-level. They come in a variety of types: memory foam and/or polyurethane mattresses, latex mattresses, etc.
But that doesn't necessarily mean that thickness is a sign of quality. Thicker mattresses can still be of poor quality. Generally, a mattress less than 20 cm thick simply offers less comfort and durability.
Natural latex may be an exception. A 15-cm-thick layer of natural latex (with a total height of 16 to 18 cm including the cover) may be adequate. It provides good comfort, but we recommend thicker mattresses for a higher quality of sleep (18 to 20 cm of natural latex without the cover).
C. Height between 20 and 25 cm
High-quality mattresses are generally more than 20 cm thick, a thickness that provides optimal support and comfort.
However, this criterion isn’t everything; you also need to consider the mattress’s construction. A thick mattress with a low-quality core offers little comfort and has a shorter lifespan. Choose high-quality materials for a comfortable core that will ensure a restful night’s sleep. We provide details on the thicknesses for each type of mattress material in Chapter II.
D. Mattresses thicker than 25 cm
These are mainly spring mattresses. Mattresses made with synthetic foam may be 25 cm thick or more, but in those cases, you should check the mattress’s density.
In addition, a mattress of this height requires optimal ventilation to prevent bacterial growth and moisture buildup inside the mattress.
Also check your bedding. Most fitted sheets have a depth of up to 25 cm.
CRITERIA TO CONSIDER
A. Age
Depending on age and height, our needs vary. Therefore, these factors must be taken into account when determining the appropriate mattress thickness.
Babies need a firm mattress to provide optimal support, with a fairly high density. However, given their weight, mattresses that are between 8 and 12 cm thick are ideal for them.
As your child grows, you’ll need to adjust their mattress. Children need a mattress that’s soft yet firm enough to provide the support they need to grow properly. We recommend a mattress thickness between 12 and 20 cm.
As noted in Part I, these mattresses are not suitable for adults. Read on to find out what thickness to choose based on the materials the mattress is made of.
B. Materials
It's true that considering the height of the mattress is essential. However, you should also check its composition, since the materials used in the mattress also affect its thickness.
In addition, the filling should not be too thick, because it is made of lightweight fibers and can quickly become hollow. For this reason, the filling should not extend more than 2 to 3 cm beyond each side of the cover.
Finally, if the mattress core is of high quality, there is often a correlation between thickness and durability. A core that is thick enough will generally last longer.
C. How thick should a latex mattress be?
For certain materials, such as natural latex, a thick mattress is usually the key to great comfort. Latex mattresses are suitable for all ages and body types. We recommend a core thickness of at least 18 cm for optimal comfort.
At Kipli, for example, we’ve chosen a 20-centimeter core (15 cm + 5 cm) for our adult natural latex mattress (22 cm total thickness including the cover). The baby model is 10 cm thick, and the children’s model is 15 cm thick. They have a long lifespan (15 years for natural latex, 10 years for synthetic latex).
D. What is the ideal thickness for a memory foam mattress?
When it comes to memory foam mattresses, it is recommended to choose mattresses that are at least 18 cm thick. The synthetic foams used in memory foam mattresses are often combined with polyurethane (or high-resilience foam) in multiple layers.
However, even a thick layer of these foams won’t guarantee a long mattress lifespan, as they tend to sag quickly. The lifespan is often limited to 7 years. More information on mattress lifespan in this article.
E. Spring Mattresses
Inner-spring mattresses are often quite thick—more than 20 cm. They offer good breathability. For better sleep independence, it’s best to choose a mattress with pocket springs. The springs have a fairly long lifespan.
However, the lifespan of these mattresses also depends on the foam used in combination with the springs on the mattress’s surface to provide cushioning. Most often, this foam is synthetic and therefore has a limited lifespan (about 10 years). When natural latex is used instead of synthetic foam, the lifespan of a spring mattress is about 12 years.
OTHER FACTORS TO CONSIDER WHEN BUYING A MATTRESS
A. Density
As explained earlier, a mattress’s density is important because it is an indicator of firmness. It should not be the same for a child as for an adult, or for a petite person as for a larger one. It is the scale that determines the mattress’s density level, ranging from the softest to the firmest.
Please note that a high density in one material does not necessarily mean it is firmer than a material with a lower density. For example, polyurethane foam with a density of 30 kg/m³ may be firmer than natural latex with a density of 70 kg/m³.
Polyurethane foam is, by definition, a firm foam because the cells that make it up result in less air within the foam. Thus, a polyurethane foam mattress can be considered firm even with a density of just 50 kg/m³.
For this type of foam, density is a key factor in determining the mattress’s lifespan. In fact, the denser a polyurethane foam mattress is, the slower it will sag. As you can see, when discussing density, it’s important to consider the mattress’s composition.
Here’s how to choose the best density for a latex mattress. For those who prefer firm support, a high-density mattress is recommended. Note that natural latex mattresses can have a density of up to 90–95 kg/m³. A density of 65 kg/m³ provides a soft feel, 75 kg/m³ offers a medium feel, and 85 kg/m³ or higher provides a firmer feel.
To learn more, we invite you to read our article “Everything You Need to Know About Different Mattress Densities”
To ensure proper support, you should also choose the density of your mattress based on your weight. If you sleep with a partner, you should also take your partner’s weight into account. Here are more details on how to choose a mattress based on your weight.
B. Size
In addition to thickness, you should consider your height when choosing the right mattress. The standard size for a single bed is 90x190, and 140x190 or 160x200 for a double bed. However, we recommend choosing a mattress that is 10 to 15 cm longer than your height to prevent your feet from hanging off the end of the bed and to ensure greater comfort.
When choosing a mattress for children, it's important not to focus solely on their age. Instead, you should take into account their height and growth rate to avoid having to replace the mattress too often.
As for width, the wider your mattress is, the more comfortable you’ll feel—especially if you sleep with a partner. However, you should take the size of your bedroom into account so that your bed doesn’t look out of proportion.
C. Bed Frame
When purchasing your bedding, be sure to choose your box spring carefully. In fact, the box spring accounts for up to 40% of your mattress’s firmness. Choose flexible slats for a soft feel and rigid slats for firmer support.
It’s important to choose the right mattress support to ensure a restful night’s sleep. Here’s some more information to help you make an informed decision: How do you choose a box spring?
D. Sleeping Position
Sleeping on your stomach is the least recommended sleeping position. In this position, your spine and neck are not properly aligned and receive little support. If you sleep in this position, you should avoid sleeping on mattresses that are too soft.
When sleeping on your side, certain parts of your body—such as your shoulders, hips, and neck—require different levels of support. It is therefore advisable to choose mattresses with zoned support for greater comfort, as well as mattresses that are slightly softer.
On your back, your weight is distributed fairly evenly, and your back is the area that requires the most attention. Most mattresses provide adequate support for this area, so choosing one shouldn't be difficult. Our advice is to choose a mattress that is neither too firm nor too soft.
After reading this article, you’ll know everything there is to know about mattress thickness. We hope this information will help you choose the best mattress for you. If you have any questions, feel free to contact us via chat, by email at help@kipli.com or by phone at +33 (0)1 76 42 11 72.
Of course,
The Kipli Team