Firm vs. Soft Mattress

Last Updated On October 11th, 2023
Firm vs. Soft Mattress

Key Takeaways

  • Importance of Mattress Firmness: The firmness of your mattress is crucial for the quality of your sleep. The right mattress firmness can help your muscles fully relax and keep your spine in a safe, neutral position, leading to a more restful night’s sleep.
  • Tailored to Your Sleep Position: Whether you sleep on your side, back, stomach, or a combination of these, there are mattresses designed to meet your specific needs. Your preferred sleep position influences the ideal firmness level for your mattress.
  • Consider Body Weight: Your body weight plays a role in determining the right firmness level. Lightweight sleepers may benefit from softer surfaces for better contouring, while heavier sleepers may require firmer mattresses to prevent sinking. The choice between firm and soft also depends on your personal comfort preferences.

The mattress you rest on each night plays an important role in the quality of your sleep. If you frequently wake up in the middle of the night with sore muscles or feel unrested throughout the day, your bed may not be supporting you correctly.

Based on your body type and preferred sleep position, you need a certain mattress firmness so your muscles can fully relax. When you are resting in a healthy, tension-free position, you’re more likely to sleep soundly and wake feeling refreshed.

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Whether you are a side, back, stomach, or combination sleeper, there is a mattress designed for your specific needs. Throughout this article, we will help you determine the level of comfort that is right for you, whether it be firm or soft.

What Makes a Comfortable Mattress?

When you climb into bed at the end of a long day, you want a mattress that feels comfortable and inviting. You also want a bed that will cushion your pressure points and keep your spine in a safe, neutral position. When resting on a supportive and even surface, the tension that builds-up in the body throughout the day can finally dissipate—leaving your muscles in a more relaxed state.

As you relax, it is vital that the heaviest parts of the body, such as the hips and shoulders, don’t sink too far into the bed. If this happens, the spine will be forced out of alignment—resulting in pain and stiffness upon waking.

By taking your body weight into account, you can determine that correct firmness level for you. Lightweight sleepers tend to need a softer surface to experience more contouring, while heavier sleepers need a firmer bed to prevent sinking.

However, your body weight isn’t the only thing to consider when deciding between a firm and a soft mattress. Throughout this article, we take an in-depth look at the advantages and disadvantages of both firm and soft beds.

Best Amerisleep Firm and Soft Mattresses

Quick Guide: A 30-Second Summary

Best Firm Mattress Amerisleep AS1
Best Medium-Firm Mattress Amerisleep AS2
Best Medium-Soft Mattress Amerisleep AS4
Best Plush Mattress Amerisleep AS5 Hybrid

The AS1 mattress possesses a firm feel to keep the body on top of the mattress. The surface limits sinkage, a helpful feature for stomach sleepers who want to prevent spinal misalignment.

Mattress Highlights
  • Minimal design for a low-profile and firm surface
  • Memory foam eases pressure points all over the body
  • Sturdy poly-foam core for spine support
Recommended For
  • Stomach sleepers
  • Select back sleepers
  • Hot sleepers

As is the case with all of our memory foam mattresses, the top layer of the AS1 mattress is Bio-Pur® foam. What sets Bio-Pur® apart from other memory foam formulas is how we replace certain traditional petrochemicals with plant-based oils. Not only does this create a more eco-friendly foam, but the final result is also more breathable and responsive than traditional memory foam.

Similarly, the base of the AS1 is the same material that forms the final layer of all our memory foam mattresses, Bio-Core®. The durable structure of Bio-Core® foam is the main reason we offer a 20-year warranty on all our mattresses.

Along with the lengthy warranty, every Amerisleep mattress includes a 100-night sleep trial and free shipping.

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For some sleepers, a purely firm mattress can feel stiff and uncomfortable. Sleepers who desire firm support often find that a medium-firm mattress like our AS2 is far more in line with what they seek.

Mattress Highlights
  • Medium-firm feel can ease aches and prevent pain
  • Transition foam with five targeted support zones
  • Structural foam promotes ideal spine alignment
Recommended For
  • Back sleepers
  • Some stomach sleepers
  • Heavier sleepers over 230 pounds

Our AS1 is the firmest option we have, and for some sleepers, it feels too firm. If you want a firm mattress that doesn’t feel like lying on a hard board, we recommend our AS2 mattress.

The AS2 has a similar structure to the AS1, containing a comfort layer of responsive Bio-Pur® foam and sturdy Bio-Core®. The top layer of Bio-Pur® foam provides a cool, adaptable cushion. The layer is just as thick as in the AS1, but the feel is mildly more conforming thanks to the underlying layers.

What mainly separates the AS2 from the AS1 is its transition layer. Underneath the Bio-Pur® foam is another unique foam layer, Affinity foam with HIVE® technology.

This middle layer establishes five zones of targeted support through a series of hexagonal cutouts. These cutouts ensure the mattress feels softer in the shoulders and hips for more pressure relief while feeling firm elsewhere.

All Amerisleep mattresses are protected by a 100-night sleep trial and a 20-year warranty.

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Our AS4 mattress is an excellent mattress for side sleepers, thanks to its thick top layer of memory foam. The AS4 hugs the body’s curves and offers extra pressure relief in the shoulders and hips, thanks to HIVE® technology.

Mattress Highlights
  • Four inches of pressure-relieving Bio-Pur® foam
  • Middle of Affinity foam with HIVE® for extra support
  • Mattress structure reinforced by Bio-Cor® foam
Recommended For
  • Side sleepers
  • Petite sleepers
  • Eco-conscious shoppers

Our best soft-but-not-too-soft mattress is the AS4, with a carefully constructed medium-soft surface. It is available solely as a memory foam mattress.

The thick 4-inch top of Bio-Pur® maximizes pressure-relieving cushion, letting side sleepers and petite individuals enjoy the pleasant sinkage after a long day. The cooling structure of Bio-Pur® ensures it won’t grow hot while hugging the body, while its responivnes keeps sleepers from feeling stuck.

Next is a thin layer of Affinity foam with HIVE® technology, creating targeted pressure relief and support. This transition layer balances out the Bio-Pur® foam cushion, ensuring it’s not too soft or unsupportive.

The base is Bio-Core®, providing needed spine support and promoting a sturdy structure.

The AS4 is backed by a 100-night sleep trial and a 20-year warranty.

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The AS5 Hybrid pairs a pressure-reliving cushion with a responsive transition foam and a pocketed coil support core. While we offer a pure memory foam mattress, many sleepers prefer the feeling of the AS5 Hybrid over the original AS5.

Mattress Highlights
  • Bio-Pur® balanced by Active Flex transition foam
  • Pocketed coils have wrappings to isolate motion
  • Reinforced edges make movements easier
Recommended For
  • Side sleepers of all sizes and shapes
  • Heavier sleepers seeking soft support
  • Sleepers seeking a plush mattress with edge support

Our softest model is the AS5 Hybrid, carefully designed to balance top-of-the-line plushness with maximum support. Poorly made soft mattresses can feel unsupportive and cause misalignment, but that’s not a danger with the AS5.

As with most of our mattresses, the top layer is Bio-Pur® foam. This thick foam top hugs the body, easing pressure points in sensitive areas.

The second layer of Active Flex is unique to the AS5 model. This material is designed to increase the responsiveness of the top layer without negating its soft feel. The adaptability of Active Flex ensures sleepers won’t sink too far and uncomfortably bottom out on the mattress’s coils.

Those pocketed coils that provide support are individually wrapped to provide independent reactions to movements. In other words, the smallest motion won’t ripple across the surface as they would in an open-coil mattress. The pocketed coils along the sides are also thicker than the rest, providing edge support to make it easier to move in and out of bed.

The coils rest on a firm foam base. The purpose of this base is to increase the mattress’s overall structure, giving the coils a sturdy base to bounce off so they won’t sag prematurely.

We also offer a memory foam counterpart to the AS5 Hybrid with the original AS5 mattress. Instead of containing a support core with pocketed coils supported by a foam base, the classic AS5 relies on Affinity foam and Bio-Core foam.

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What’s the Difference Between a Firm and Soft Mattress?

When shopping for a new mattress, you have likely noticed that each one comes with a “firmness level.” But, how is this level determined? Many brands rely on a standard firmness scale from 1 to 10—with 1 being the softest and 10 being the firmest. Firm and soft mattresses are at opposite ends of this scale. That said, you’ll rarely find mattresses rated as a 10 or a 1 because those are extremely firm and extremely soft beds that aren’t commonly made.

A firm mattress rates between a 9 and a 7 on the firmness scale. These beds have very little give, so the surface tends to remain even and allows for little sinking.

A soft mattress rates between a 2 and a 3 on the firmness scale. These beds compress quickly and easier when pressure is applied. Most sleepers experience some level of sinking when resting on a soft bed.

Mattress Types and Firmness

Different types of mattresses utilize different materials, which can also affect the firmness. The following are the four most common mattress styles and the firmness levels you can expect with each.

  • Memory Foam Mattresses: Memory foam is available in several different firmness options. Depending on the manufacturing process, memory foam can be either soft or extra firm. When shopping for a memory foam bed, look at the type of memory foam used and the layers supporting it to determine the firmness it will provide.
  • Latex Foam Mattresses: There are two types of latex foam—Dunlop and Talalay latex. Dunlop tends to have a firmer firm, and these beds are typically considered medium-firm. Talalay latex is generally treated with additives to give it a soft to medium feel. Both materials have a natural elasticity that offers a slight bounce.
  • Hybrid Mattresses: Hybrid mattresses have a stable coil base and a foam comfort layer. The type of foam used in the top of the bed will determine the firmness you will experience.
  • Innerspring Mattresses: The coil springs in the base of an innerspring bed give it a firm feel. These beds tend to have a thinner comfort layer, so they are classified as either medium-firm or firm.

Advantages of a Soft Mattress

When you rest on a mattress, there is usually some space between your body and the surface of the bed. For some sleepers, this open space can leave certain areas of the body unsupported. On a soft mattress, the material quickly forms to the body like a glove, ensuring that every curve is protected. A soft bed comes with the following advantages.

Suitable for Side Sleepers

When side sleeping, the hips and shoulders bear the brunt of the body weight. Resting on a firmer mattress can cause pressure to build up near these sensitive areas. This tension could force you to toss and turn to find comfort—resulting in lost hours of sleep. We usually recommend soft mattresses for side sleepers because they will keep the body cradled and supported to alleviate tension.

Since some soft mattresses tend to promote sinking, be sure to select one that has enough responsiveness to keep the torso lifted, so the spine remains neutral.

Suitable for Lightweight Sleepers

Firm vs Soft Mattress
Whether resting on their side, back, or stomach, lighter individuals (those 130 pounds or less), will naturally experience very little sinking. If these individuals sleep on a firm mattress, tension can build-up near the pressure points—creating pain and stiffness. Lightweight sleepers need a soft bed that will quickly respond to their body weight for adequate contouring.

Comfortable for Those With Arthritis and Joint Pain

Those with arthritis and joint pain tend to find relief with a softer mattress that cushions sensitive areas. If these sleepers rest on a firm mattress, it could force the body into uncomfortable sleep positions that exacerbate pain.

The spine should also be kept in a neutral position to alleviate tension. Therefore, the torso must not sink too far down. If you are a heavier sleeper with arthritis, you may be more comfortable on a medium mattress.

Reduces Pressure Points

A firmer mattress can sometimes cause pain and pressure to build-up along the curves of the body. With a soft bed, this is less likely to happen. Whether an all-foam or hybrid style, soft mattresses will cradle pressure points to alleviate tension and reduce pain.

Drawbacks of a Soft Mattress

Soft mattresses often promote sinking. However, if certain parts of the body fall too far, the spine’s natural curve could become exaggerated. Therefore, it is best to look for a soft bed with a response layer that gives the body a slight lift, so the spine remains neutral.

Since soft beds contour so closely to the body, they can also cause overheating. When shopping for a soft mattress, be sure to select one with cooling properties, such as breathable, plant-based foam, cooling gel microbeads, or copper infusions.

Advantages of a Firm Mattress

A firm mattress keeps weight evenly distributed, so no one part of the body needs to bear all of the pressure. Since these beds offer very little sinking, the spine is more likely to remain in a safe, neutral position. A firm mattress comes with the following advantages.

Suitable for Back and Stomach Sleepers

When resting on the back, the hips and buttocks tend to sink. If the mattress is too soft, these areas may sink excessively—resulting in a misaligned spine and tense muscles. Back sleepers tend to sleep best on a firmer bed that will prevent sinking and keep the hips in line with the shoulders and head. When the spine is neutral, the body can fully relax and repair.

Our spines naturally curve, but when sleeping the stomach, this curve can become exaggerated. Over time, the pressure this position places on the back and neck can lead to chronic pain. In most cases, it is best to avoid stomach sleeping. However, if you find it difficult to avoid this position, the best mattresses for stomach sleeping are firmer. A firm bed will keep the hips lifted to reduce the pressure on the spine.

Suitable for Heavy Sleepers

Those over 230 pounds will experience more sinking than a lightweight sleeper. If the mattress is too soft, a heavier person will sink too far and hit the harder support base on the bottom of the bed. Resting on the hard core of the bed could cause pain near the pressure points.

Additionally, sinking can cause the sleeper to feel stuck in the bed, making it difficult to change positions during the night. This restricted movement could also lead to poor circulation and trouble breathing. With a firm mattress, the lungs can expand and blood can flow freely.

Prevents Overheating

A soft mattress will naturally offer more insulation as it molds to the body. If you’re a hot sleeper, a soft mattress could cause overheating and sleep interruptions. Firm beds allow more air to flow across the surface of the bed, so you are less likely to wake due to night sweats.

Improves Circulation

The close contouring that comes with a soft mattress could restrict movement, and, therefore, circulation. If you suffer from heart disease or diabetes, a firmer bed is the best option. A firmer surface will keep the body lifted, rather than sunk, allowing for more blood flow and healing.

Drawbacks of a Firm Mattress

A firm mattress is not for everyone. Side sleepers may experience pressure build-up along the sides of the body on a firm bed. Lightweight individuals may not experience enough sinking on a firm mattress—causing spinal misalignment and muscle tension.

A firm bed may help support the lumber and relieve lower back pain. However, those with arthritis and joint pain need a mattress that will hug the curves of the body for pressure relief.

Firm vs. Soft Mattress Overview

A firm mattress is best for….

  • Heavy sleepers (those over 230 pounds)
  • Back sleepers
  • Stomach sleepers
  • Hot sleepers

A soft mattress is best for….

  • Lightweight sleepers (those less than 130 pounds)
  • Side sleepers
  • Those with arthritis and joint pain
  • Those in need of pressure relief and contouring

Frequently Asked Questions

How do I know if my mattress is too firm?

If you are a side sleeper, look for the following signs to determine if your mattress is too firm.

  • You experience pain and stiffness near pressure points, such as your hips and shoulders.
  • Your arms quickly fall asleep with little pressure.
  • You frequently wake with back pain due to a misaligned spine.

Back sleepers tend to benefit from a firmer mattress. However, if you can place a hand between the lumbar (the lower curve of the spine) and the mattress, you may want a bed with a bit more softness, such as a medium-firm bed.

Do firm mattresses get softer?

If your mattress is firmer than you expected, it may soften up over time. Some mattress materials, such as memory foam, respond to pressure and body heat so they can soften up a little. However, innerspring beds are made of spring coils and have very little foam, so they will not become softer with use.

Are firm mattresses bad for side sleepers?

Side sleepers need a mattress that offers pressure point relief while also keeping the body supported. A soft to medium mattress is typically a good option for side sleeping. When decided between a soft or a medium mattress, be sure to consider your body weight. If you are under 130 pounds, a soft to medium comfort level will offer you more contouring. If you are over 230 pounds, a medium firmness will cradle pressure points and prevent sinking.

How can I make my bed more firm?

You can change the feel of a mattress by adding a topper. Memory foam toppers can be used to add softness or firmness to your bed. At Amerisleep, our Lift Memory Foam Topper comes in two different firmness levels—Support and Comfort. If you are looking to add firmness to your current mattress, the Support topper has a firmer feel and helps create an even sleeping surface. The Comfort topper offers more cushioning for those looking to add softness to a bed.

Is a soft mattress good for back pain?

The best mattress for back pain is one that promotes a healthy spinal position. When the hips and shoulders are in line, the muscles in the back can relax. A medium-firm to firm mattress offers the most relief from back pain.

Can I test out the mattress and return it if it’s not right for me?

Many online mattress companies offer free sleep trials that allow you to rest on the bed for up to 100 nights. If you decide the mattress is not supporting you correctly, they will issue a full refund. With a free trial period, it is easy to make sure the mattress is right for you.


Without proper rest, you may feel run-down, irritable, and groggy. Plus, lost hours of sleep can lead to slower cognitive function, poor decision making, and a compromised immune system. The first step toward a good night’s sleep is a comfortable and supportive mattress. As you shop, be sure to keep your personal preferences in mind, as well as your body type and sleep habits. A mattress suited to your needs will help you sleep soundly throughout the night and wake ready for the day.

About the author

Mitchell Tollsen is a graduate student and a freelance writer who’s contributed to the Early Bird blog for three years. Mitchell’s always been fascinated by the science of sleep and the restorative processes our bodies undergo when at rest. The self-titled “Sleep Expert” is always looking for ways to improve his shut-eye, and throughout the years has implemented numerous lifestyle changes and tried dozens of sleep-promoting gadgets to determine the best ways to truly get better rest.

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