Best Memory Foam Mattress — Getting Down to Core Issues

The best memory foam mattress has these features:

  • High density rating
  • ILD range of 12-16
  • Good Resiliency
  • Foundation Core at least 4-5 inches thick
  • Layered construction, with firmest (highest density) foam in the core, and less firm layers on top


A high density foam will hold up under years of use. High density means more foam (mass) and less air. As you can imagine, a low-density foam with lots of air simply won’t offer enough support and will compact down very easily.

Density does not measure firmness — that is rated by ILD numbers. It’s possible for a low-density foam to feel firm, as firmness has to do with how the material is made, not with how dense it is.

Density is measured by the weight of a cubic foot. So one cubic foot of 5-lb density foam will weigh 5 pounds.

But be careful — a high-density rating is not always an indication of the best mattress. Some cheap memory foam mattresses have a deceptively high density rating because they use more “filler” –added material that is not high-quality memory foam — to add density.

To be fair, some fillers are added for legitimate reasons, such as reducing flammability or increasing strength. But there is no excuse for adding unnecessary fillers to reduce costs and deceive buyers into believe the mattress they’re looking at is better than it really is.

Assuming you are not dealing with a deceptive manufacturer and the purity of your mattress is fine, look for at least a 4-lb density rating.

Tempurpedic uses 5.3 density in their mattresses, and as they certainly qualify as one producer of the best memory foam mattress, we can use their specifications as a guideline for evaluating the competition.


This stands for indentation load deflection. It determines the hardness or softness of the foam. The higher the number, the firmer it is. ILD is measured by testing how much weight is necessary to indent a 4-inch thick block of memory foam by 25 percent of its thickness. So you can see why higher numbers mean greater firmness. If it takes 20 pounds to compress the material by 25 percent of its height, then the ILD rating is 20. If it only takes 10 pounds, that is a softer mattress.

In the best memory foam mattress, the ILD of the top layers should be between 12 and 16 (13 and 15 is even better) — not too hard, not too soft — for ultimate comfort and support. Firmness is of course an individual preference, but it’s important to stay away from extremes for best results.


The best memory foam mattress has good resiliency — that means it will spring back to its normal shape quickly. This means you are dealing with a high-quality material.

However, do keep in mind that the “memory” part of this material means it will never offer the instant spring-back qualities of latex or poly foam. It will always stay compressed longer than these other materials. This is the inherent quality that some will like… and others won’t.

It is unlikely that you will get any numbers or ratings on resiliency, but it is one feature that you’ll be able to test yourself when you lie down on the bed and stay in one position for at least 15 minutes. Then get up and watch how long it takes for the surface to even out again. Sometimes you can’t tell because the layers of padding will hide the indentation. In that case, simply lie down on it again to feel whether your body impression is still there or has gone away.

Inside Structure

Now let’s talk about a rather tricky subject — the inner core of the best memory foam mattress. Here is the big mystery. Some of the mattresses will have inner cores made of firm memory foam. Others will have cores made of firm poly foam.

Let’s get one thing straight. Memory foam and polyurethane foam share some of the same chemical characteristics, but they are NOT the same material. They do not behave the same. And they do not function or perform the same.

It is unlikely that any mattress retailer will give you the exact specifications and measurements of the insides of their mattresses. However, if you are doing cost comparisons, you can be certain of this: the lower the price, the more poly foam you will be getting inside the mattress. This is in addition to other cost cutting features, such as lower density ratings and more additives.

But even the best memory foam mattress may have some poly foam. It makes sense to use this material in the inner core of the mattress where it adds firmness, resiliency, support, bulk and thickness to a mattress.

But the best memory foam mattresses do NOT have an eight-inch core of poly foam covered by two inches of memory foam to give you impression that you are getting a 10-inch memory foam mattress. If such a mattress is labeled “memory foam” — it is simply misleading advertising.

If you are getting an 8-inch thick polyurethane core and two inches of viscoelastic foam, but paying memory-foam prices, you are definitely overpaying. You can get a much better deal by buying a firm poly mattress and adding a 2-inch memory foam topper. It will be a far cheaper alternative and at least you’ll know exactly what you’re getting.

Tempurpedic (let’s face it, this company is still the gold standard for memory foam mattresses) has a layered construction that features a firm base of poly foam — but it is only a base. On top of that are layers of memory foam of appropriate densities and firmness, with the numbers getting lower and the feel getting softer as they move up. This is how the best mattresses are constructed.

If you skimp on the inner core, using a softer or less dense material, you will compromise both durability and long-term comfort of the mattress.

Where to Find the Best Memory Foam Mattress

Once you are armed with the information to insure you’re getting the best memory foam mattress available in your price range, it’s time to go looking.

For best prices, check out general discount stores, such as Costco and Wallmart, or mattress discount stores and online retailers.

For better customer service, check out your local stores and retailers.

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