A Complete Guide to Memory Foam Densities and Their Qualities

A Complete Guide to Memory Foam Densities and Their Qualities

There are mattress brands all over the internet telling you that they have the best memory foam mattress offering fantastic features. The only thing that they have in common is the promise of the best night of sleep, but are they all true? 

Today we look into mattress density to look at how to correctly evaluate the mattress quality since there is a strong correlation between these two. 

When you compare brands, there might be too many factors to look at and foam density is one of the most important features and specs to sort through since it relates to durability, quality, and individual comfort. 

What are foam density ratings?

Density is a measurement of how heavy it is compared to its size. A truckload of feathers, for example, will weigh less than a truck full of steel. That’s because feathers are less dense than steel, as this equation explains Density = Mass/Volume.

Most things have density measurement or ratings, memory foam is also such. In the case of memory foam, they are usually measured by the pounds per square foot. The densest varieties have a rating of 8.0 or 8 pounds per cubic square foot.

With the density number, you understand how durable the bed is as well as how soft or firm it feels. With this knowledge, you have a north star when it comes to choosing the mattress. 

The lower the number, the less foam there is contained in the production, which means less expensive and feels softer. It also means that you won’t expect a long life from a mattress of a rating of fewer than 3 pounds per cubic square foot.

Less dense foam mattresses are ideal for occasional usages such as guest beds or camping scenarios. They could also work for children or people who are extremely light.  

How is foam density measured in numbers?

Density is the measurement of weight per unit of volume, in the case of foam, it means pounds per cubic foot. In other words, the density of the foam is expressed by measuring the weight of a single cubic foot of foam material

As an example, consider a foam layer that weighs 100 pounds and measures 25 cubic feet in total. By dividing the total weight by the total number of cubic feet, we can see that this layer has a density of 4 pounds per cubic foot (4 PCF).

Manufacturers will list out the materials included in the foam, and you need to check the PCF to understand its density level and firmness level. 





Memory Foam

Less than 3 PCF

3 to 5 PCF

More than 5 PCF


Less than 1.5 PCF

1.5 to 1.7 PCF

More than 1.7 PCF

As it shows, the high-level density of Polyfoam is very different from the memory foam. This is because of the materials of each type of foam. 

To avoid mistakes and confusion, we advise you to be sure to double-check the type(s) of foam and not just the density rating.

What does each density level mean?

Memory foam densities


As we mentioned above, a density level less than 3PCF is ideal for guest and leisure usage or people with less weight as this mattress is not as durable as the higher density ones. 

These types of foam mattresses are soft and less stable with a comparatively lower quality setting. 


Measurements of 4 to 5 pounds per cubic foot are classified as medium-density. This range is rated by most people as not soft nor too hard, but just right. 

Normally unless you have a very unusual weight level or prefer an extra soft or firm mattress, this range is for most users. 


The number for the high-density foam is over 6 cubic feet or higher, these beds will be more expensive and of higher quality. 

As highly durable as it is if you need a bed as an investment or firm support for the back or past injuries, this bed is ideal since it offers solid support. 

The bed itself usually needs a bit of time to break in since it might seem a bit too firm at first.

What else could foam density be translated into?

Pressure withstand

Foams with a higher density score will feel more firm and can withstand higher pressure, and lower score ones can not withstand as much pressure. 

Higher-density memory foams also recover more slowly after pressure is applied to them. 

Because of these properties, a mattress could consist of a mix of foams with various density levels, each layer is of different foam materials and different density ratings. 

Denser foams are typically more durable than low-density foams, and will not sag as much over time. On the other hand, low-density foams tend to offer better temperature regulation, which can be an important use for those living in warm climates. 


The most obvious factor to consider for firmness is its density rating, but this number does not represent everything since some foams can be designed better than others, this density measurement is not the only factor for its firmness. 


As density levels rise, usually so does the price. This is primarily due to the amount of material that’s used to make something that’s the same size. A high-density bed has more foam in it than a lower one, which increases the cost.

So in other words, you might get what you paid for. And what potentially could be the best deal is that if the mattress is of higher density good quality foams but still charges relatively fair, in this case, look no further than Hesperis Mattress since we know what we are talking about. 


Contouring is usually what attracts a lot of people to memory foam mattresses. Its hugging feeling gives you the warmth and comfort of home and dream.

In terms of density, the higher the density, the less contouring you can expect, although all memory foam beds, regardless of their number, will respond to your body heat and weight and provide some give.

Response time

You might have seen a lot of pressing hands into the foam, then the lasting handprint follows, the print lingering time is usually the sign of the response time. 

The lower density score ones bounce back faster since there is more air within the foam. A high-density brand will keep the imprint of your weight longer, which also makes it a bit more of a challenge to roll over when it’s time to get up or switch positions.


You already know that the denser the material, the heavier it is. Therefore, a high-density viscoelastic mattress will weigh more than one that has a lower number associated with it.

If you plan to move around or carry a mattress upstairs, you might consider a lighter one for that matter. Or inquire about the company and whether they will assist with the moving services. 

Sleep quality

Sleep is a matter of personal preference. Some people prefer a softer bed with lots of contouring while others prefer a firm surface. 

A 120-pound person will perceive the firmness of a bed differently than someone who weighs 200 pounds. The lighter person won’t sink as much as the 200 pounds ones. 

Therefore, heavier individuals may want to seek out higher density materials, whereas lightweight people may prefer a lower density rating.


Does high-density foam mean it’s a firm mattress?

Even though high-density ratings are often associated with firmer surfaces, that’s not the only variable that affects how a mattress feels.

Another important number to look at is the indentation load deflection (ILD). This number indicates how much force is required to put a one-inch dent in the material. It’s tested with a giant machine that presses down a piece of foam and tracks the power exerted. The higher the ILD number, the firmer the bed.

What thickness and density level is best for mattress toppers?

The answer to this question depends on the reason you’re buying a mattress topper. If your bed is too firm, and you’re looking for a way to soften it, then a 2 to 3-inch thick topper with a low to medium density will provide the most amount of comfort.

If your bed isn’t supportive enough or you’re trying to extend the life of your mattress, look for a topper that’s 3 to 4 inches thick and has a higher density.

What density level is good for side sleepers?

Side sleepers tend to need a softer mattress that contours well to the body’s curves. The reason is that when people sleep on their side, the weight of their shoulders and hips presses deeply into the surface. A typically recommended density is approximately 4.0, but there’s a wide range that many will find acceptable.


We understand that the density could be confusing and unfamiliar, but instead, it could be an important metric to measure the level of firmness and quality as well as the price of the mattress. As a good benchmark, it is worth the time to understand the ins and outs of this index and use it to the best of your knowledge to purchase a mattress for your needs. 

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