Mattress Firmness Guide
What Level Is Right For You?
By Chelsea King | Published April 10, 2026
Choosing a new mattress is exciting — until you hit the firmness question. Soft? Medium? Firm? Extra firm? What does any of it actually mean for your sleep? The good news is that finding your ideal mattress firmness isn't a guessing game. It comes down to three things: how you sleep, your body type, and whether you share a bed with someone whose preferences are very different from yours.
At Mathis Sleep, we carry over 300 mattresses across every firmness level — from our exclusive in-house brands like Americana, William & Lawrence, and IntelliGrid to nationally recognized names like Tempur-Pedic, Purple, and Beautyrest. This guide cuts through the confusion so you can walk into any of our Mathis Sleep locations — or shop online — and know exactly what you're looking for.
Mattress firmness is rated on a 1–10 scale. Side sleepers do best at 4–6 (soft to medium); back sleepers at 5–7 (medium to medium-firm); stomach sleepers at 6–8 (medium-firm to firm). Sleepers over 230 pounds may find a mattress feels softer than its rating suggests, and may want to go one level firmer than their sleep position alone would indicate. When in doubt, medium-firm (5–6) works for the widest range of sleepers. Mathis Sleep carries options at every level with free delivery and the 365 Dream Program for members.
Mattress Firmness
What Does Mattress Firmness Really Mean?
Mattress firmness describes how soft or hard a surface feels when you lie down — and it's measured on a standard 1–10 scale. A rating of 1 is the softest imaginable; a 10 would feel completely unyielding with no give whatsoever. In practice, nearly every mattress on the market falls between a 3 and an 8. Where you fall on that scale depends on how you sleep, your body type, and what comfort feels like to you.
It's critical to understand that firmness and support are not the same thing. Firmness is about how the mattress feels — how much you sink in. Support is about how well the mattress keeps your spine in neutral alignment. A soft mattress can be beautifully supportive for a side sleeper. A firm mattress can feel supportive to a back sleeper without providing any pressure relief at all. Both qualities matter; they just do different jobs.
At Mathis Sleep, every mattress we carry is rated by comfort level — Extra Soft, Soft, Medium, Firm, and Extra Firm — so you can filter by feel the moment you start browsing.
Side Sleepers
What Mattress Firmness is Best for Side Sleepers?
Side sleepers need a mattress in the soft to medium range — typically a 4–6 on the firmness scale. When you sleep on your side, your shoulder and hip are the widest points of your body, and they press directly into the mattress. A surface that's too firm won't contour to those curves, creating uncomfortable pressure points that lead to shoulder pain and hip soreness by morning.
Our Americana Corina Soft Mattress is built precisely for this sleep style, with CertiPUR-US® certified foam comfort layers that cradle pressure points without sacrificing core support. For a more premium option, the William & Lawrence Corby Soft Mattress layers individually wrapped coils beneath a plush comfort system, delivering that contouring feel with the added responsiveness of a hybrid construction. If you're a lightweight side sleeper under 130 pounds, you may actually want to go slightly softer — the ecocomfort Ultra Conform Medium hits that sweet spot with an adaptive foam system designed for consistent pressure relief across different body types.
Back Sleepers
What Mattress is Best for Back Sleepers?
Back sleepers do best on a medium to medium-firm mattress — a 5–7 on the firmness scale. Sleeping on your back distributes weight across a larger surface area than side sleeping, so you need a mattress that supports the natural lumbar curve of your spine without letting your hips sink so deeply that your lower back bows. A mattress that's too soft will put you in a hammock position; too firm, and you'll feel unsupported at the small of your back.
The Americana Acacia Medium is one of our most popular picks for back sleepers — it delivers that balanced, supportive feel with a CertiPUR-US® foam system that keeps hips level and spine aligned. If you want to step up the construction, the William & Lawrence Buckden Medium combines zoned coil support with multiple comfort layers for targeted pressure relief through the lumbar region. For back sleepers who prefer the immersive feel of memory foam, Tempur-Pedic's TEMPUR-Adapt Hybrid Medium uses proprietary TEMPUR® material that conforms deeply to the body while returning to shape, night after night.
Stomach Sleepers
What Mattress is Best for Stomach Sleepers?
Stomach sleepers need a firm to extra-firm mattress — a 6–8 on the firmness scale, and sometimes higher. Sleeping on your stomach puts your hips at risk of sinking too deeply, which causes the lumbar spine to arch unnaturally and leads to chronic lower back pain. The firmer the surface, the more your hips stay elevated and aligned with your shoulders.
The Americana Brissa Firm and Americana Finnley Firm are both purpose-built for stomach and back/stomach combination sleepers, with dense support cores that resist deep sinkage. For stomach sleepers who want a premium firm option with advanced construction, the IntelliGrid Nexus Premier uses a proprietary grid system with individually wrapped coils — it maintains exceptional firmness at the surface while providing zoned support that prevents hip drop. Stomach sleepers should avoid memory foam as their primary comfort layer, as viscoelastic foam tends to conform too deeply around the hips.
Body Type
How Does Your Body Type Affect Mattress Firmness?
How a mattress firmness feels in practice depends significantly on your body type — and it's one of the most overlooked factors in mattress shopping. A mattress rated 6/10 (medium-firm) will compress differently under different body weights, because more weight engages the support core more deeply, which changes how the surface feels.
As a general rule: sleepers under 130 pounds may find mattresses feel firmer than their rating suggests, since the comfort layers engage less deeply — going one level softer than your sleep position indicates is worth considering. Sleepers over 230 pounds may find the same mattress feels softer than rated, as the comfort layers compress more deeply — going one level firmer can compensate for this. For sleepers between 130–230 pounds, standard position-based recommendations typically apply as described.
Soft vs. Medium vs. Firm: Quick Comparison
| Firmness Level | Scale Rating | Best For | Mathis Sleep Pick |
|---|---|---|---|
| Soft | 3–4 | Side sleepers, lightweight sleepers under 130 lbs | William & Lawrence Corby Soft |
| Medium | 5–6 | Back sleepers, combination sleepers, couples with different preferences | Americana Acacia Medium |
| Medium-Firm | 6–7 | Back sleepers, combination sleepers, most sleepers 130–230 lbs | EcoPerfect Verdant Medium, Tempur-Pedic TEMPUR-Adapt Hybrid |
| Firm | 7–8 | Stomach sleepers, back sleepers over 230 lbs | Americana Finnley Firm, IntelliGrid Nexus Premier |
| Extra Firm | 8+ | Stomach sleepers over 230 lbs, those needing maximum spinal support | William & Lawrence Askerton Firm, QUBE Mattress collection |
Sharing a Bed
What's the Best Mattress Firmness if You Share a Bed?
The best mattress firmness for couples is medium-firm (5–7 on the scale) — it's the single level that works adequately for the widest range of sleep positions and body types. Medium-firm tends to be the most workable compromise for two people with different sleep preferences.
If you and your partner have significantly different needs — say, one is a side sleeper who wants soft and the other is a stomach sleeper who needs firm — a split-comfort mattress or adjustable base is the right solution. Mathis Sleep carries adjustable bases from Purple, Tempur-Pedic, Thrive, and Sealy that allow independent head and foot positioning, giving each partner a customized sleep surface. The Purple Rejuvenate 2 is worth exploring for couples: Purple's proprietary GelFlex® Grid adapts to different body shapes and sleep positions simultaneously, making it one of the most versatile firmness options on the market for shared beds.
Frequently Asked Questions About Mattress Firmness
How do I know when to replace my mattress?
Most mattresses should be replaced every 7–10 years, depending on the material and how heavily the mattress is used. Common signs it's time for a new one include visible sagging, waking up feeling stiff or unrested despite a full night's sleep, or noticing that you sleep better away from home than in your own bed. If your mattress is more than 8 years old and you're no longer sleeping comfortably, it's worth exploring your options at Mathis Sleep — our sleep specialists can help you find the right replacement.
What is the difference between mattress firmness and mattress support?
Firmness is how soft or hard a mattress feels when you lie down on it. Support is how well the mattress keeps your spine in neutral alignment throughout the night. The two are related but not the same — a soft mattress can be highly supportive for a side sleeper if it cradles the hips and shoulders correctly, while a firm mattress may lack adequate support for certain body types. When shopping at Mathis Sleep, our specialists evaluate both factors together to help you find the right match.
How do I know if my mattress is too soft or too firm?
If your mattress is too soft, you'll sink into a "hammock" shape overnight and wake up with lower back pain or stiffness. If it's too firm, you'll feel pressure building at your shoulder, hip, or knee contact points and may wake up numb or sore. Most quality mattresses require a 30–60 day break-in period before you can accurately judge the feel — this is why Mathis Sleep's 365 Dream Program lets you exchange your mattress within a full year.
Can I try a mattress before I buy it at Mathis Sleep?
Yes — and we strongly encourage it. Mathis Sleep has 24 locations across Oklahoma, Texas, Arkansas, and California where you can lie on any mattress in your actual sleep position for as long as you need. Wear comfortable clothes, bring your partner if you share a bed, and spend at least 5–10 minutes on each mattress. Our sleep specialists are available to help at no charge.
What is the 365 Dream Program?
The 365 Dream Program is Mathis Sleep's mattress comfort guarantee for Mathis Rewards members — it gives you a full year to decide if your mattress is the right firmness. If you're not sleeping well after a proper break-in period, you can exchange for a different comfort level. It's the most generous trial in the region.
Ready to Find Your Perfect Mattress?
Browse mattresses by comfort level online, or visit any of our Mathis Sleep locations for a free in-store sleep consultation. Members get the best prices — join Mathis Rewards to unlock Member pricing and the 365 Dream Program today.
Chelsea King is an SEO specialist at Mathis Home, specializing in furniture retail and eCommerce. With a background in education and finance, she creates research-driven, consumer-first content to help shoppers make confident, informed buying decisions.