Memory Foam Mattress Density

What is Memory Foam Density?

Memory foam density refers to the weight of one cubic foot of memory foam (a 12-inch cube). Memory foam is available in different densities which do affect a few essential characteristics of mattresses.

Although we can learn the weight, softness, support, durability about a memory foam mattress by knowing its density, the only thing density tells us for sure is how much it weighs.

For example, if the density of a mattress is 4 lbs/ft, it means that a cubic foot of the foam weighs 4 pounds.

Many memory foam mattress brands provide customers with a wealth of density options.To learn the density of some popular foam mattress brands and models, see Memory Foam Brands Comparison.

Low-Density VS. Medium-Density VS. High-Density

The common range of memory foam densities is between 2.5 pounds and 7.0 pounds. Generally speaking, low-density foams are below 3.5 lbs/ft, medium-density foams are between 3.5 and 5.0 lbs /ft and foams over 5.0 lbs/ft are considered high density.

Low Density (2.5 - 3.9 lbs/ft)

Low-density memory foam mattress feels softer and makes you sink in. They can't compete with high-sensity mattresses when it comes to long lifespan and superb support, but they are more affordable. If you have a tight budget or like the sink-in feeling, then a low-density memory foam mattress is a suitable choice.

Medium Density(4.0-5.4 lbs/ft)

Mattresses with medium-density can be a good choice for most people since they offer above-average comfort, durability, and support with a very reasonable price. They are neither too soft nor too stiff. If you don't have a clue about what you’re looking for, a medium-density memory foam mattress can do no wrong.

High Density(5.5 lbs/ft+)

High-density mattresses have better support and durability. For people suffering from back pain, high-density memory foam can relieve pressure points and improve circulation. The high-density memory foam may feel stiff initially, but it will mold to your body after a while.

Memory Foam Density Comparison

Low Density
(2.5 - 3.9 lbs/ft)
Medium Density
(4.0-5.4 lbs/ft)
High Density
(5.5 lbs/ft+)
Affordable Price
7
4
2
Durability
5
6
7
Conforming Ability
5
7
9
Back Pain Relief
6
7
8
Motion Isolation
7
8
9
Good For Sex
4
3
1
Fast Responding
7
4
1
Floating Feel
7
8
9
No Initial Odor
3
2
1
No Sleeping Hot
4
3
2
Avg-Size Person Friendly
8
9
9
Heavy Person Friendly
8
9
7
Light Person Friendly
7
5
2
Short Break In
6
3
1
Easy to Lift
5
3
1

What do We need to Know?

Density ≠ Thickness

It's important to know that memory foam density and thickness are two separate and different qualities. Density is the inside cell structure while thickness refers to the actual height of the mattress.

Density ≠ Firmness

Density and firmness of a memory foam are not necessarily related, but density does have an effect on how a mattress feels. A denser memory foam mattress has a narrower cell structure, which makes it initially feel firmer until it contours to the body. Firmness depends more on the depth, layers and the ambient temperature (for temperature sensitive foams) of the mattress. Soft, medium or firm mattresses can all be made from the same density. It's common to see low, medium and high-density mattresses that provide options from soft to firm.

Density & Price

High-density memory foam mattress costs much more than low-density one. A memory foam with 6 lbs/ft density can cost thousands of dollars.

Density & Durability

Although the manufacturing technique also affects overall durability of a mattress, density has no doubt to be the significant predictor of lifespan. Low-density foams have less resistance to compression compared to high-density ones. The base layer of a mattress needs to be heavy and strong enough to provide the core support. As we all know, a high-density base layer weights more than low-density ones. On average, one can expect a low-density memory foam mattress to last about 5 years, while medium-density one lasts 7-8 years and high-density foam last 9-10 years.

Density & Heat, odor

The higher the density, the narrower the cell structure. A tight cell structure means poor ventilation which leads to a bigger possibility of heat retention. Also, a tight cell structure means smaller space between cells, so the foam will take up less moisture and become more compact.

Denser foams tend to have bigger off-gassing problems because of more use of chemicals compared to low-density ones.

The Higher ≠ The Better

Denser foams can be more reactive and affected by temperature, becoming softer in a warm room and firmer in a cold room. A foam with higher density tends to feel very viscous like being trapped in quicksand, which makes it difficult to change positions or get of bed.

When it comes to general comfort and pain relief, medium and higher density foams tend to perform better than low-density models. Low-density foams are less reactive and return to their former shapes faster.

Each one has a different preference when talking about density, so whatever suits you is the best.

Not All The Layers Are of The Same Density

Most memory foam mattresses have several layers with different densities.For instance, it's common to see a mattress equipped with a low-density top layer and a high-density bottom layer.

It is important to know clearly what the density of each layer because a low-density foam is much cheaper than high-density one. You don't want to pay the high-density price for all the layers, only to find out only the top layer is high density.

How to Determine Which Density Suits You The Best

The suitable firmness of a memory foam mattress mainly depends on your personal preference, size, and sleeping position.

  • A low-density foam is similar to a soft mattress, a medium-density foam is similar to a medium mattress, and a high-density foam is similar to a firm mattress.
  • If you have no clue about mattresses, a memory foam with a low-density top layer and a high-density base layer can provide both comfort and core support.
  • If you suffer from neck or back pain, then a high-density mattress is a suitable choice for its effective pain relief.
  • If you are a side sleeper, a low-medium density mattress will offer the softness and comfort you need.
  • If you are a back or stomach sleeper, a low-medium density mattress suits you the best.
  • If your sleeping position often varies, then a medium-density mattress can do no wrong.
  • Couples who have different sleeping habits can always purchase a high-density mattress and add a low-density topper to improve comfort.

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