Firm vs. Soft Mattresses

If you’re waking up sore or unrested every morning, it may have nothing to do with your sleep position or daily activities—you could just have the wrong mattress. When shopping for the best mattress, you can’t just go down to the furniture store and pick the first one that feels nice.

Comfort is important, but there are other factors that just as strongly influence what kind of mattress you need. Your ideal firmness level is dictated not only by your personal preferences but also by your body type and sleep style.

Firm and Soft—What’s the Difference?

Mattress firmness is measured on a scale of 1 to 10, with 1 being the softest. However, it’s very rare to find mattresses softer than a 3 or firmer than an 8—a lot of manufacturers don’t make extra-soft or extra-firm mattresses because they’re too extreme for most consumers. (However, with a little bit of digging, you can find comfortable extra-firm and extra-soft mattresses sold by certain brands.)

Soft mattresses will generally land somewhere around 3 on the firmness scale, while firm mattresses come in around an 8. Manufacturers rate their own mattresses, so there might be a little bit of variance from one mattress company to the next, but most of the time this variance will be small enough you still know what you’re getting.

Firm Mattresses

Firm mattresses are better for back sleepers, stomach sleepers, and heavier sleepers (230 pounds and up) because they don’t compress as much as soft mattresses, keeping stomach and back sleepers’ spines aligned and body weight evenly distributed. They’re also good for hot sleepers because they’re not overly cradling, so body heat can escape out of firm mattresses more easily.

Pros

• Promotes spinal alignment for back and stomach sleepers
• May help with back pain for some sleepers
• Can usually accommodate heavier sleepers
• Sleeps cooler

Cons

• Can cause pain and pressure points for side sleepers and people with more petite frames
• Not overly comfy
• May not offer enough cushion for people with joint pain

The AS2 is not a true firm mattress, but the medium-firm surface of the AS2 suits more sleeping styles than a purely firm mattress. We recommend it for back sleepers who want to avoid sore backs, along with lightweight stomach sleepers. The AS2 is also beneficial for plus-size sleepers over 230 pounds.

The AS2 mattress has three foam layers, wrapped in a soft, breathable cover fabric.

The first layer is Bio-Pur® foam, a unique innovation of traditional memory foam. While the average memory foam is wholly synthetic, Amerisleep’s Bio-Pur® foam is partly plant-based. The result is a foam that’s more breathable and responds faster than traditional memory foam.

The middle layer is Affinity foam with HIVE® technology. This special feature relies on hexagonal cutouts to establish five zones of support, creating areas where the mattress feels more conforming for needed pressure relief. The back area focuses on support for minimal misalignment, ensuring sleepers wake up refreshed and pain-free.

The last layer is a thick base of Bio-Core® foam, a sturdy material that extends the mattress’s lifespan. Amerisleep has such faith in the durability of Bio-Core® foam that they offer an industry-leading mattress warranty.

Sleepers who are interested in a true firm mattress may want to consider the AS1 offered by Amerisleep instead. The AS1 has a similar design to the AS2, only it lacks the Affinity foam layer with HIVE® technology. This design choice establishes a surface with a consistently firm feel.

Amerisleep backs every mattress with a 100-night sleep trial and a 20-year warranty.

Soft Mattresses

Soft mattresses are normally a better option for side sleepers and lighter weight sleepers, as their soft surfaces relieve pressure points around the shoulders and hips and compress enough to cushion even the lightest of sleepers.

Pros

• Reduces pressure points
• Comfortable for people with certain conditions like arthritis, scoliosis, sciatica, etc.
• Better for lighter weight sleepers

Cons

• May not support spinal alignment for back and stomach sleepers
• May cause sinkage for heavier sleepers
• May sleep warmer than firm mattresses since they offer more cradling

The AS5 is the softest mattress Amerisleep offers, designed to provide for sleepers who need that extra bit of pressure relief or who enjoy a mattress that embraces their body instead of keeping them firmly on top of the bed.

As with the AS2, the AS5’s first layer is breathable and responsive Bio-Pur® foam. This layer is thicker than in the AS2 for more cushion. Underneath the Bio-Pur® foam is a layer of Active Flex, engineered to limit sinkage without affecting the bed’s plush feel.

The AS5’s main supportive layers consist of the Affinity foam with HIVE® technology and the Bio-Core® base. As with the AS2, the Affinity foam with HIVE® provides five zones of targeted support, while the Bio-Core® foam promotes a durable mattress structure for ideal spine alignment.

Like with the AS2, Amerisleep offers the AS5 Hybrid as an alternative for people who enjoy a spring mattress. Sleepers who enjoy a mattress that’s soft but not too soft can also consider the company’s medium-soft option, the AS4.

The AS5 is backed by a 100-night sleep trial and a 20-year warranty.

Finding the Best Firmness Level for You

Your preferred sleep position is the number one thing you need to think about when deciding on mattress firmness. How you sleep at night dictates where you’re most likely to experience pressure points, which part of your body is going to compress the bed the most, and how the bed is going to distribute your weight.

For sleepers who don’t enjoy soft or firm mattresses, a medium mattress is often best. For more information, refer to:

• Soft vs. Medium Mattress
• Firm vs. Medium Mattress

Back Sleepers

Sleeping on your back means your hips and buttocks tend to sink into the bed, so a firm mattress is a good option to keep the heavier parts of your body lifted, your weight evenly distributed, and your spine aligned. You want your mattress to be firm enough that it supports your pelvic area, but not so firm you can put a hand between your lumbar region and the mattress like you’re lying on the floor.

Side Sleepers

Side sleepers’ pressure points need extra cradling, meaning a softer mattress will probably be better for them. While in the side sleeping position, you want your shoulder and hips to compress the mattress enough so the joints are cushioned but your torso and legs are still supported—keeping your spine straight and your hips aligned. Side sleepers can get comfy sleep on a soft mattress, but some side sleepers like medium mattresses, too.

Interested in learning more about the best mattresses for side sleepers? Check out our other review guide.

Stomach Sleepers

When it comes to finding the best mattress for stomach sleepers, it’s important to consider the potential effects on your spine. Sleeping on your stomach can cause your spine to arch too much, leading to chronic low back pain over time. Stomach sleepers need a firm mattress to counteract this effect, as a firm mattress can keep the hips lifted and the spine in a neutral position while sleeping on your belly.

Combination Sleepers

If you like to change positions a lot during the night, we recommend a medium mattress. Medium mattresses can offer you both enough compression to cushion your shoulder and hip joints when you’re on your side as well as enough firmness to lift your pelvis when you’re on your back or stomach. Mediums also won’t compress so much that they make moving around during sleep more difficult.

Overall, the best mattress for combination sleepers is one that can support you in all sleeping positions while still providing a comfortable sleeping surface.

Choose the Right Mattress Size

Mattresses of all firmnesses come in the standard mattress size run.

FAQs

Does mattress material affect firmness?

A mattress’s material affects a lot of things, from feel to heat retention to durability to motion transfer, but it has little impact on how hard or soft your mattress is. All mattress types are available in all firmness levels, meaning you’ll be able to choose between firmness levels whether you buy memory foam, latex, hybrid, or innerspring.

Is my mattress too firm or too soft?

Waking up with pain in some part of your body is generally the first clue something’s off with your mattress firmness. Side sleepers may experience pain and stiffness around pressure points or frequently wake up to find their bottom arm has fallen asleep, and both of these issues are signs you may need a softer mattress. Conversely, if you’re a stomach or back sleeper and waking up with lower back pain every morning, your mattress may need to be firmer.

How much softer will my mattress get over time?

Most mattresses soften up eventually, but how much they soften depends on the type of mattress. Innerspring mattresses won’t lose a noticeable amount of firmness after you purchase them. But foam mattresses can react to pressure and body heat, meaning they’ll lose some firmness once you bring them home and sleep on them for a few weeks. That’s why it’s vital to ensure your mattress comes with a (risk-free) trial period of at least 90 days. That way, you can return it (for free) for a refund if it turns out it doesn’t work for you.

What if my partner and I need different firmnesses?

Split kings are a great option for couples with vastly different firmness needs. A split king allows you to buy a king sized bed frame and put two twin XL mattresses on it. That way, you can both choose the mattress model of your ideal firmness. As an added bonus, the split king allows couples to use split adjustable bed frames and adjust each side of the bed to their desired angle for sleeping.

Does firmness make a difference in how long a mattress lasts?

Possibly, but not that much. Firmer mattresses might be a tad more resistant to sagging, but the quality of your mattress materials and construction, and how well you take care of it, are going to have a whole lot more to do with how long it lasts than firmness does.

If you want to make your mattress last longer:

• Use a mattress protector to shield it from stains, bed bugs, and other germs.
• Wash bed linens regularly.
• Properly support your mattress with a quality mattress foundation or platform.

Additionally, having a reliable mattress warranty in place can provide added peace of mind and protect your investment in the event of any unexpected issues.

Bottom Line

As you can see, your ideal mattress firmness level can be influenced by a lot of important considerations, from your body weight to your favorite sleep position. Even if you spend a year researching the best mattress for you, you’ll never really know if it’s a perfect fit until you try it out for a month or two. All mattresses come with an adjustment phase of a few weeks to a couple of months, so whatever you do, don’t get a mattress without a sufficient trial period—it’s the best thing to determine the right mattress for your needs.