Density Guide

Last Updated: August 2017

Now that you’ve decided that a memory foam mattress is a right choice for you, there are several other factors that you need to consider. No matter which brand or manufacturer you choose, you will need to consider the memory foam mattress density. Foam mattress density can have a tremendous impact on your comfort, pain relief, and support, so understanding density and how to choose the right one for your needs is important. This memory foam mattress density guide will help you make that choice.

Understanding Memory Foam Density

The density of a memory foam mattress is measured in pounds per cubic foot. Thus, if you purchase a mattress that claims a 3lb density, you can expect that each cubic foot of that mattress will weigh right at three pounds. The lower the density, the softer the mattress. Conversely, the higher the density, the firmer the mattress will be. Remember that many of today’s manufacturers offer layered mattresses that contain a high-density support layer topped with a lower-density comfort layer. For most people, this variation in the density of foam offers the right balance.

The Differences between a Low, Medium, and High-Density Memory Foam Mattress

Low-Density Memory Foam

Low-density foam is characterized by anything that weighs three pounds per cubic foot or less. This is the softest, most conformable memory foam out there, and it will wrap around your body, allowing you to sink into the bed somewhat. This foam density offers up all of the softness you would expect from a “soft” traditional innerspring mattress. However, a lower-density foam cannot provide you with the same amount of support that a high-density foam can, so be sure that you choose a mattress with a dual-layer design. The bottom layer should be at least five pounds in density.

Medium Density Memory Foam

Most people prefer medium density foam because it provides the perfect balance between softness and support. These mattresses fall in the four to five pounds per cubic foot range, which makes them perfect for anyone who has a difficult time determining what sort of mattress they should purchase. Medium density also works well for couples, particularly if one person prefers softness and the other prefers firmness. For the most part, everyone can agree on the comfort level offered by medium density foam.

High-Density Memory Foam

High-density memory foam is still soft for the most part, but it has been designed to mimic the overall feel of a traditional firm mattress. This foam weighs six pounds per cubic foot or more, and it is often the most expensive type of memory foam on the market. All orthopedic mattresses should have a density of at least six pounds since this is considered the therapeutic level of support. This means that if you often wake up with aches and pains, or if you have specific orthopedic medical needs, you should shop for high-density foam mattresses. What’s more, higher density foam tends to hold up longer than lower density options, so your investment will last for years to come.

Foam Density and Mattress Toppers

Now that you understand the differences between different foam densities, you might find yourself wondering what you should do if you want to purchase a foam mattress topper for your existing innerspring or memory foam mattress. For instance, if you find that your high-density memory foam bed is too firm, you can add a topper to help change the way the bed feels beneath your body.

However, it is important to note that if you chose a bed with medium density foam for the support layer, adding high-density foam sheets to the top of the mattress will not truly provide you with additional support. The thicker layer, which is only medium density, will conform to your weight over time and still not provide the support you need. For this reason, if you cannot decide between a medium or high-density foam bed, we recommend choosing the one that offers a higher density support layer. Even if you add a 4-pound density memory foam mattress topper later, you can rest assured that the support layer (which is a higher-density foam) is still cradling your body and relieving potentially painful pressure points as you sleep.

To get the best results from a memory foam mattress topper, you should purchase one that is at least four inches thick. For instance, if you choose a 4 lb density memory foam mattress topper that is only two inches thick, you are not likely to notice much difference since your weight will compress the low-density product greatly. Choosing a topper that is four or more inches thick provides much more space for this compression, which will keep you more comfortable.

What is the Best Density for a Memory Foam Mattress?

This is a difficult question to answer because the best density for a memory foam mattress truly depends on your needs and personal preferences. Below, we’ve summarized a few tips and pointers to help you decide once and for all.

  • A low-density foam is equivalent to a soft mattress, a medium density foam is equivalent to a medium mattress, and a high-density foam is equivalent to a firm mattress.
  • Most manufacturers layer the foam with a high-density support layer on the bottom and a softer, lower density comfort layer on the top. This is very important, because, without that support layer, the mattress would be unable to properly support your body.
  • If you are a back or stomach sleeper, a higher density foam will probably feel better to you as you sleep.
  • If you are a side sleeper, a medium density foam does a better job of conforming itself to your pressure points and keeping your spine in alignment.
  • Couples who have difficulty agreeing on a firmness can always purchase a higher density mattress and add a lower density topper, but the memory foam mattress topper should always be no fewer than four inches thick.

As you can see, you truly need to put a lot of thought into choosing the perfect memory foam mattress. Memory foam density is a very important consideration, and making the right choice is imperative to your overall health and comfort. When you choose the right density memory foam, you will truly feel as if you are sleeping weightlessly on a cloud, and you will wake to feel completely refreshed.

Take a look at our essential guides:

Mattress Guides

Pillow Guides

Topper Guides

General Guides


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