Memory Foam Mattress Buying Guide: What to Look For

When buying a memory foam mattress, match firmness to your sleeping position first, then check the foam type for heat, thickness for your body weight, CertiPUR-US certification, and a sleep trial of at least 100 nights. Side sleepers usually want 3 to 6 out of 10, back and combination sleepers 5 to 8, and stomach sleepers 7 to 10.

This guide covers who memory foam suits, a firmness chart, how the layers and foam types differ, sizes, certifications, trial and warranty terms, budget, and how memory foam compares with hybrid and latex beds. For background on the material itself, see what memory foam is and how it works.

How to Choose a Memory Foam Mattress

Choose a memory foam mattress by working through these steps in order, since firmness and support shape how a bed feels far more than any extra feature.

1. Match firmness to your sleeping position and weight. Use the firmness chart below as your starting point.
2. Decide whether the memory foam feel suits you. Restless and warm sleepers have the most to weigh.
3. Check the layers and thickness. Look past the total height to what each layer does.
4. Pick a foam type for temperature. Warm sleepers should start with the cooler foam types.
5. Choose a size that fits the people sharing the bed and the room it goes in.
6. Confirm CertiPUR-US certification on the foam layers.
7. Read the trial and warranty terms before you buy, not after.
8. Set a budget and compare beds within it.

Is a Memory Foam Mattress Right for You?

A memory foam mattress suits you if you want close contouring and a quiet bed that absorbs movement, and it suits you less if you change positions often or tend to run warm at night.

Contouring is the main reason to choose memory foam. It compresses under the parts of the body that stick out, such as the hips and shoulders, and fills in where the body curves in, such as the waist and lower back. That spreads pressure and keeps the spine closer to neutral, which is why memory foam shows up so often among the best mattresses for pressure points.

The trade-offs are response time and heat. When I change positions, I note how quickly the surface adjusts, because a slow recovery is what restless sleepers tend to notice first. If either trade-off is a deal breaker, the comparison with hybrid and latex beds near the end of this guide shows where those materials differ.

Memory Foam Firmness by Sleeping Position

Your sleeping position sets your firmness range, and your body weight fine-tunes it. On Sleep Junkie’s 1 to 10 scale, where 1 is softest and 10 is firmest, these are the ranges to shop within.

These ratings assume a sleeper of about 130 to 230 pounds. If you weigh under 130 pounds, go one step softer so the foam compresses enough at the shoulder and hip. If you weigh over 230 pounds, go one step firmer, since a heavier body sinks further into foam; for picks built with that in mind, see the best mattresses for heavy people.

Lying on my side, I pay attention to pressure at the shoulder and hip, which is the quickest way to tell whether a bed is too firm for side sleeping. To narrow your options by position, compare the best mattresses for side sleepers, the best mattresses for back sleepers, the best mattresses for stomach sleepers, and the best mattresses for combination sleepers. Back and stomach sleepers often meet in the middle on a medium-firm mattress, and the mattress firmness scale guide explains each level in more detail.

How a Memory Foam Mattress Is Built

A memory foam mattress is built from at least two foam layers, and often three or more: a soft comfort layer on top, an optional transition layer in the middle, and a firm, high-density support core at the base.

Foam Density

Foam density, measured in pounds per cubic foot, affects how long each layer holds its shape and how quickly it responds. The memory foam mattress density guide explains the ranges and what they mean for each type of sleeper.

Thickness

Thickness is a rough guide to how much cushioning sits above the support core, not a measure of quality on its own. Side sleepers and heavier bodies tend to need a thicker comfort layer so they do not sink through to the firm base, while stomach sleepers and lighter bodies usually do well on a thinner, firmer build.

Types of Memory Foam

Memory foam types differ mainly in how much heat they hold and how quickly they spring back, so the right one depends on how warm you run and how much you move.

If you tend to run warm, pair a cooler foam type with a breathable cover, and look at the best cooling mattresses for builds that add airflow. To judge heat, I compare how warm each surface feels by touch through the first hours against the other beds I am testing.

Memory Foam Mattress Size Chart

The right size depends on how many people share the bed, how tall you are, and how much floor space you have.

A full is snug for two adults, since each person gets 27 inches of width, so most couples are happier on a queen or larger. For a daybed, measure the frame before choosing between twin and twin XL, then compare daybed mattresses in that size. Oversized beds such as the Texas, Wyoming, and Alaskan king mattresses are harder to find, and so is bedding to fit them.

If you are weighing sizes for a specific bed, the Amerisleep AS3 comes in twin, twin XL, full, queen, king, California king, and split king.

Certifications and Off-Gassing

Look for CertiPUR-US certification on a memory foam mattress, because it means the polyurethane foam was tested by independent labs for content, emissions (low VOC), and durability.

New foam often gives off a smell for the first several days or weeks after unboxing. This is called off-gassing, and it comes from volatile organic compounds (VOCs), carbon-based chemicals that the EPA notes evaporate at normal indoor temperatures and can come from household furnishings. The smell usually fades as the mattress airs out in a ventilated room, and certified low-VOC foam tends to produce less of it.

Two other labels are worth checking, as long as you know what each one covers:

• OEKO-TEX STANDARD 100: textiles, such as the cover, tested for a list of harmful substances.
• GREENGUARD Gold: products tested for low chemical emissions into indoor air.

A certification applies only to the part of the mattress it names, so check whether a label covers the foam, the cover, or the whole bed.

Sleep Trial and Warranty: What to Check

Look for a sleep trial of at least 100 nights and a warranty of at least 10 years, and read the terms of both before you buy.

Sleep Trial

Memory foam can take a few weeks to break in, so a shorter trial may end before you know whether the bed suits you. Check whether returns are free, whether you must keep the mattress a minimum number of nights before returning it, and whether you get a full refund. If comfort is your top concern, compare those terms across the most comfortable mattresses on your list.

Warranty

A long warranty shows how long the maker expects the materials to hold up. Read what counts as a defect, how deep a body impression must be before it is covered, and whether the warranty requires a particular type of base. Clear terms with little fine print are a good sign.

How Much Should You Spend on a Memory Foam Mattress?

Memory foam is one of the more affordable mattress types, usually costing more than a basic innerspring but less than a comparable hybrid or latex bed.

Price depends on size, foam density, layer thickness, and extras such as gel or a cooling cover. Higher-density foam costs more up front but tends to hold its shape longer, and because memory foam has no coils to lose tension, a well-made all-foam bed tends to outlast a basic innerspring, which can lower its cost per year. Compare like for like, such as one queen size mattress against another, and start with the best budget mattresses if price is your main limit.

Most memory foam beds ship compressed in a box, which is a big part of why so many are sold online. Browse the best mattresses in a box or the best mail order mattresses to compare options that ship to your door.

Memory Foam vs Hybrid vs Latex

Choose memory foam for the closest contouring, a hybrid for more bounce and airflow, and latex for the fastest response and a natural-material build.

A hybrid pairs foam comfort layers with a pocketed coil support core, so it keeps much of memory foam’s contouring while responding faster and letting more air move through the bed. The hybrid mattress buying guide covers coil types and layer builds, and the best hybrid mattresses show current picks.

Natural latex comes from the sap of the rubber tree and pushes back as soon as you move. It is the main option if you want an organic foam mattress; look for GOLS certification, which means the latex is made with at least 95 percent certified organic raw material. Learn more about the benefits of a latex mattress, read the latex mattress buying guide, or compare the best latex mattresses. For every other material, see the guide to types of mattresses.

Bottom Line

The right memory foam mattress starts with a firmness rating that fits your sleeping position and weight, then a foam type that suits how warm you run, CertiPUR-US certified foam, and a sleep trial of at least 100 nights. For one medium pick that covers side, back, and combination sleeping, the Amerisleep AS3 is a good place to start. To compare more options, see the best memory foam mattresses.

Frequently Asked Questions

How long does a memory foam mattress last?

A memory foam mattress lasts as long as its foam keeps its shape, which depends mostly on foam density, the depth of the support core, and how much weight the bed carries each night. Higher-density foams tend to hold up longer. Replace the mattress when you see lasting body impressions, sagging in the middle, or a surface that no longer springs back.

Does memory foam trap heat?

Memory foam can trap more body heat than latex or coil beds because it contours closely and leaves less room for air to move around you. Open-cell, gel-infused, plant-based, and copper or graphite infused foams tend to trap less heat than traditional memory foam, so warm sleepers should look for one of those types and a breathable cover.

Can you sleep on a memory foam mattress right away?

Yes, you can usually sleep on a memory foam mattress the first night, even though many brands suggest waiting up to 24 hours for it to fully expand. A newly unboxed bed may feel a little firmer and look slightly flat at first, and any new-foam smell fades faster in a ventilated room. Read more about sleeping on a memory foam mattress before 24 hours.

Do you need a box spring for a memory foam mattress?

No, a memory foam mattress usually does best on a solid platform, a closely slatted base, a foundation, or an adjustable base rather than a traditional box spring. Wide gaps between slats or springs can let the foam dip and wear unevenly over time. Check the warranty before you set it up, since many makers list the types of support they require.

Should you flip or rotate a memory foam mattress?

Rotate a memory foam mattress head to foot every few months, but do not flip it unless the maker says it is two-sided. Most memory foam beds have a soft comfort layer on top and a firm support core underneath, so sleeping on the underside puts you on the wrong layer. Rotating spreads wear more evenly across the surface.