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Memory Foam Density: A Complete Guide to Memory Foam Densities and Their Ratings

Posted By: Layla

When you lay down at night, sinking ever so softly into your memory foam, you’re probably not thinking about the density quotient of your mattress. You just know it feels like your bum is being cradled by cotton candy.

Memory Foam Density: A Complete Guide to Memory Foam Densities and Their Ratings

The reality is that not every memory foam mattress is created with the same density – and it could affect your sleep experience. 

Do you need a low-, medium-, or high-density bed? Does mattress foam density affect how you feel in the morning? Just when you thought it was down to the difference between memory foam vs spring mattresses, it turns out there are a few more decisions to make.

Let’s dive into these questions and more in our memory foam density guide for curious sleepers. 

What is Memory Foam Density?

Let’s start with the basics. Memory foam density is often confused with firmness. More specifically, some people think that a firmer mattress must be a denser one. Which kind of makes sense. 

Except it’s not that simple. 

Density refers to how heavy something is compared to its size. Density = mass/volume. For memory foam, the volume considered is one cubic foot. So, the heavier one cubic foot of memory foam is, the higher the density rating of the mattress

The manufacturer determines the density of memory foam by adding more or fewer particles to the cubic foot in question. As we mentioned, that doesn’t necessarily mean making it firmer.

Firmness is measured using something called indentation load deflection (ILD), which refers to the amount of weight needed to compress the foam by 25%. You could have a high-density memory foam mattress that – because of the type of foam that’s used – is still fairly soft.

What Does Mattress Density Affect?

If memory foam density doesn’t always determine the firmness, what does it affect? We’re glad you asked. The weight per cubic foot of your memory foam bed can make a big difference in things like how long the mattress lasts and how hot you get at night. 

Let’s talk about the way that your bed’s density impacts your overall sleep experience. 

Motion Transfer

How do you tackle the age-old problem of not waking up your partner in the middle of the night? With a memory foam mattress of course! A memory foam mattress tends to perform better than a spring mattress when it comes to motion absorption. 

But when it comes to memory foam density, higher density foam almost always isolates movement entirely compared to a lower density foam.


Do you want a mattress that lasts? Of course, you want a mattress that lasts! And denser mattresses are more likely to stand the test of time. Low-density foam is more susceptible to wear and tear due to the lower concentration of material.

We can’t guarantee that a high-density mattress will last forever, but we can tell you that more memory foam density is usually good for extending the lifespan of your mattress. 

Body Contouring

Many people choose a memory foam mattress because they like the idea of a mattress that conforms to their shape. Will a high-density mattress mean abandoning the idea of contouring? 

No, even high-density memory foam is designed to cradle your curves. However, you might notice a tighter hug from beds with higher memory foam density. If you’re into a super-squishy feel – you might prefer low- to medium-density at the top layer of your mattress. Likewise, if you move around a lot, a lower density mattress can better handle your frequent adjustments. 

Foam Response Time

The foam response time is the amount of time it takes your memory foam to return to its original form after you get out of bed. You know those memory foam commercials where someone puts their hand on the mattress and you see a handprint when they pull it away? That’s meant to show fast foam response time. 

As a general rule, mattresses with a higher memory foam density have a slower response time. Mattresses with a lower density have more air pockets inside, so they bounce back faster. 

Slower foam response time could mean that it’s less comfortable to roll over and readjust in the middle of the night. On the other hand, you may enjoy the more defined support of a foam that stays contoured to your shape for longer. 


It’s no surprise that the overall weight of a high-density memory foam mattress is heavier than low-density foam. After all, adding density always adds weight. 

Lifting and moving your mattress may be more difficult if you choose a bed with high memory foam density.

There is no exact science to how heavy mattresses are at each density (especially since many mattresses have varying layers). But if you’re wondering what to expect, a high-density queen mattress will often weigh around 90 pounds. 


If you sleep hot, high-density memory foam could make the issue worse. Lower density tends to have better airflow and trap less of your body heat. 

With that being said, the material the memory foam is made of also plays a part. If the foam is copper-infused, for instance, it may be able to adequately wick heat away from your body regardless of the density. 


High-density memory foam requires more material. That usually means it costs more. For people on a budget, a low- to mid-density memory foam mattress means the benefit of contouring without a payment plan. 

How Do Memory Foam Densities Compare?

Some manufacturers won’t categorize the density of their products. But you can play sleuth and figure out where your mattress belongs on a memory foam density chart if you know a little something about memory foam density ratings.

Low Density

Mattresses have a low-density rating if they have 3 or fewer pounds per cubic foot. Mattresses with this rating may still have great quality. The natural wear and tear of your sleep habits will affect these mattresses sooner rather than later, but you can often expect to get a good 10 years out of them

Medium Density

If you find a mattress with a weight of 4 to 5 pounds per cubic foot, it has a mediumdensity rating. This level of density is good for people with a higher than average body weight, and folks who are looking for something that’s not too firm, hot, or heavy. If you’re the Goldilocks of mattress shopping, consider something in this range.

High Density

Mattresses with 6 or more pounds per cubic feet are rated as high density. In terms of memory foam density, this is the most tightly compacted type of mattress. These mattresses may cost more – but they could also last well over a decade if you take proper care of them. 

Should I Choose Foam Density Based on Sleeping Position?

The best density for your comfort may be based on your sleeping position and body weight. Many other factors can contribute to how sensitive you are to different memory foam densities, including if you have a condition for back pain. But generally, here are some quick insights to consider:

  • Side sleepers benefit from low to medium density. They need the mattress to have a fair amount of give to accommodate their pressure points. If you weigh more than 230 pounds, a high-density mattress may still work for you. 
  • Back sleepers will also appreciate low- to medium-density mattresses. However, because their weight is more evenly distributed, people with a bodyweight as low as 140 pounds could also be comfortable on a high-density model. 
  • Stomach sleepers should stick to medium or high density. You’ll likely sink too far into a low-density mattress, causing your back to arch which can lead to morning pain.

Sleeping Well on a Layla Mattress

Are you counting spots in the ceiling when you should be blissfully unconscious? Welcome to the Insomnia Club, where you never slip into REM and you live on double-shot espressos.


You don’t have to live like this.

There are ways to improve your sleep and, by extension, your waking hours. It starts with the right mattress. At Layla Sleep, our cooling mattress topper and bamboo sheets are just the beginning. We also make a flippable mattress with two firmness options!

Our signature mattress has core foam center with a density of 2.0 pounds per cubic foot (PCF). The convoluted airflow layer which supports the soft side has a density of 1.8 PCF, and the copper-infused memory foam (on both sides) has a density of 3.5 pounds.

What are you waiting for? It’s time to trade in your membership in the Insomnia Club to join the community of the Well-Slept to get your days started on the right foot. It’s better over here – trust us! Try our mattress for up to 120 days, and if it’s not a good fit, you can send it back for a full refund.