The Complete Guide to Mattress Firmness: How to Choose What's Right for You

You've spent another night tossing and turning, waking up with that familiar backache. Your mattress feels either too firm—like sleeping on the floor—or so soft you're sinking like quicksand. Sound familiar?

Choosing the right mattress firmness is one of the most important decisions for your sleep health, yet it's also one of the most confusing parts of mattress shopping. Big box stores throw around firmness numbers that don't mean much, salespeople push whatever makes them the most commission, and everyone has different opinions on what "medium-firm" actually means.

Here's the truth: the right firmness can change your life. Better sleep affects your energy, mood, health, and daily performance. But the wrong firmness? That's years of poor sleep and morning aches.

At Rested Pillow, we've been making mattresses the right way in Michigan for years. There's no one-size-fits-all answer to firmness, but we can offer honest guidance based on real experience, not sales pressure or industry gimmicks. This guide will cut through the confusion and help you understand what firmness really means, how to find your ideal level, and why construction quality matters as much as the feel itself.

Why Mattress Firmness Matters More Than You Think

What Proper Spinal Alignment Looks Like

Your mattress firmness isn't just about comfort, it's about your health. Every night, your body needs proper spinal alignment and pressure relief to repair and recharge. When firmness is wrong, sleep quality suffers, impacting everything else.

You spend roughly one-third of your life on your mattress. If that surface isn't supporting your body correctly, you're setting yourself up for problems. Poor spinal alignment leads to back pain, neck stiffness, and muscle tension. Inadequate pressure relief causes circulation issues and forces you to toss and turn searching for comfort.

Studies show that the wrong mattress firmness can reduce sleep quality by up to 40%. That means less deep sleep—the stage where your body does most healing and memory consolidation. Without enough deep sleep, you wake up groggy, your immune system weakens, and stress tolerance decreases.

Proper firmness provides:

Spinal Alignment: Keeps your spine aligned, reducing nerve and muscle pressure. Too soft, and hips sink too deep. Too firm, and your shoulders can't settle properly.

Pressure Point Relief: Distributes body weight evenly, preventing pressure buildup at hips and shoulders. This improves circulation and reduces position shifting.

Temperature Regulation: Affects how much you sink in, impacting airflow around your body for comfortable sleep temperature.

Motion Isolation: Proper firmness reduces motion transfer between partners, decreasing sleep disruption.

Understanding the Mattress Firmness Scale (And Why It's Often Misleading)

The mattress industry typically uses a 1-10 scale, with 1 being softest and 10 firmest. Sounds straightforward? Unfortunately, it's not.

Here's what the industry doesn't want you to know: firmness ratings are highly subjective and inconsistent between brands. A medium-firm mattress from one company might feel completely different from another's medium-firm. There's no governing body standardizing these ratings, so manufacturers assign whatever number they want.

The Standard Scale (When Used Honestly):

• 1-2: Very Soft (significant sinking, plush feel)
• 3-4: Soft (noticeable sinking, body contouring)
• 5-6: Medium (balanced feel, moderate contouring)
• 7-8: Firm (minimal sinking, strong support)
• 9-10: Extra Firm (very little give, maximum support)

Most people prefer mattresses in the 4-7 range, but your ideal spot really depends on body type, sleep position, and personal preferences.

Why the Scale Gets Confusing:

Some big retailers manipulate firmness ratings to boost sales. They might call a soft mattress "medium-firm" because more people are drawn to that description. Some use proprietary scales that don't match industry standards, making comparisons impossible.

Terms like "luxury firm" or "plush firm" sound specific but are really just marketing language. Material types also affect feel; an all memory foam mattress rated "medium-firm" might feel very different from a traditional innerspring with the same rating.

Our Approach

The exact same mattress can feel totally different depending on your body and sleep style. A 285-pound back sleeper might think a mattress feels soft. A 100-pound side sleeper might lie on that very same bed and feel like they're on a brick. That's why at Rested Pillow, we don't use a number scale. We can't feel what you feel, but we can ask the right questions to help find your perfect fit.

Instead of pointing to a number, we'll ask: How do you sleep? Side, back, stomach, or a mix? What's your mattress history? What did you like—or not like—about your last bed? Too firm? Lost support too quickly? What's unique about you? Your build, your sleep style, your health needs—all of these play a role.

From there, we'll make personalized recommendations. Because you don't need "a number on a scale." You need the mattress that feels right for you. Our Michigan-made construction ensures our recommendations are reliable, and what we tell you about a mattress's feel will hold true years after purchase.

How Your Sleep Position Determines Your Ideal Firmness

Your sleep position is one of the biggest factors determining ideal firmness. Each position creates different body stresses and requires different support types.

Side Sleepers (Most Common)

Side sleeping creates pressure points at shoulders and hips; your body's widest parts. You need enough softness to relieve that pressure while maintaining spinal alignment.

Look for enough contouring to relieve shoulder and hip pressure, plus support that keeps your spine straight from head to toe.

Back Sleepers

Back sleeping is considered healthiest for spinal alignment, but you still need the right firmness to maintain your spine's natural curve and support your lower back.

You need balance: firm enough to support heavier body parts (hips/midsection) while providing some contouring for the lower back curve.

Stomach Sleepers

Stomach sleeping puts the most spine stress and often requires the firmest mattress. Your midsection is heaviest, and if it sinks too deep, it creates an unnatural back arch, leading to back pain.

You need firm, even support to keep your hips aligned with your shoulders and maintain a neutral spine position.

Combination Sleepers

If you change positions throughout the night, you’re likely a combination sleeper and you need firmness that works reasonably well for all positions—typically a middle ground.

Look for a balanced medium feel that doesn't excel in one area at others' expense, good responsiveness for easy position changes, and materials that work across different sleeping positions.

Firmness vs. Support: The Difference That Changes Everything

Understanding the difference between firmness and support will help you make a much better mattress decision. Many people think these terms mean the same thing, but they're quite different, and you need both.

Firmness: How the Mattress Feels

Firmness is the immediate sensation when you lie down. It's the "feel"—plush, medium, or firm. This is what you notice in the first few seconds. Firmness is largely determined by comfort layers; the top few inches of the mattress your body touches.

Support: How the Mattress Holds Your Body

Support is how well the mattress maintains spinal alignment and distributes body weight. It keeps your spine in its natural position and prevents pressure points. Support comes from the supportive core of the mattress below the comfort layers -  either hybrid coils, innersprings, or foam. 

A well-made mattress might have soft comfort layers providing pressure relief and a firm, supportive core maintaining spinal alignment.

Cheap mattresses might feel firm initially but lack support structure to maintain that firmness over time. You might think it feels supportive, but wake up with back pain because it's not actually supporting your spine properly.

How Our Construction Delivers Both

At Rested Pillow, we design mattresses to provide both the firmness feel you prefer and the support your body needs. Our pocket spring systems provide consistent, responsive support that adapts to your body while maintaining proper spinal alignment. Comfort layers on top provide pressure relief and firmness, while the support core keeps your spine properly positioned.

Finding The Right Firmness For Couples

What Split Feel and Firmness Look Like in a King Zipper Mattress from Rested Pillow

One common challenge is couples who can't agree on firmness. Partners often want different firmness levels due to body weight differences, sleep position preferences, age and health needs, or previous experience with different mattresses.

Solutions That Work:

Compromise Approach: Many couples find success with medium-firm mattresses. This provides enough support for back and stomach sleepers while offering adequate pressure relief for side sleepers.

Split Firmness Options: Our customizable zipper mattresses in a king size give couples the option of choosing their preferred firmness on either side.

Mattress Toppers: Add a topper to one side to adjust firmness if you find a mattress that works for one partner but not the other.

His & Hers Bedrooms: These days, a lot of our customers are rethinking how they sleep. Instead of compromising, they go a step further and set up their own sleep space in a separate bedroom.

It’s sometimes called a “sleep divorce,” but really—it’s not a bad thing at all. In fact, many couples find it’s the best thing they’ve ever done for their relationship. When you’re both sleeping better, you’re both living better (and usually getting along better, too!).

Communication Tips:

• Test together in your normal sleeping positions
• Be honest about health issues requiring specific support
• Consider long-term needs as preferences may change
• Both partners deserve good sleep; don't sacrifice one for the other

How Body Type and Weight Affect Your Firmness Needs

Body weight significantly impacts how any mattress feels. Heavier bodies compress materials more, experiencing different firmness levels than lighter bodies on the same mattress.

Lightweight Sleepers (Under 130 lbs) 

You won't compress materials as much, so mattresses often feel firmer than rated. You typically need softer mattresses for adequate pressure relief and contouring.

Average Weight Sleepers (130-230 lbs) 

Most mattresses are designed for this range, so you'll typically experience firmness close to advertised ratings. Your ideal firmness depends more on sleep position and preferences.

Heavier Sleepers (Over 230 lbs) 

You'll compress materials more, making mattresses feel softer than rated. You may need firmer mattresses for adequate support and to prevent excessive contouring. Pay attention to edge support and durability.

Common Firmness Mistakes (And How to Avoid Them)

Mistake #1: Assuming Firmer Always Means Better Support 

Focus on how the mattress supports your specific body type and sleep position, not firmness rating alone.

Mistake #2: Buying Based on Partner's Preference Only 

Both partners need involvement in the decision. Consider compromise solutions if preferences differ significantly.

Mistake #3: Trusting Showroom Testing Over Sleep Trials 

A few minutes in a showroom differs greatly from eight hours of sleep. Use sleep trial periods (like our 100-Night Comfort Guarantee) to get it right.

Mistake #4: Not Considering The Break-In Period 

Give new mattresses at least 30 days before deciding firmness is wrong.

Mistake #5: Ignoring Body Changes 

Reevaluate mattress needs regularly. Weight changes, aging, and health conditions can change firmness requirements.

Mistake #6: Falling for Marketing Gimmicks 

Focus on how the mattress actually feels and performs rather than marketing claims like "orthopedic" or "scientifically designed."

How Mattress Materials and Construction Affects Firmness Feel

Materials and construction methods hugely impact how firmness feels and holds up over time.

Memory Foam: Responds to heat and pressure, feeling firmer when cool and softer when warm. Density affects firmness and durability.

Latex: More responsive and bouncy than memory foam, doesn't change much with temperature. Provides firm support while contouring.

Innerspring: Gets firmness from coils themselves, but comfort layers significantly impact feel. Can have firm coils with soft layers.

Pocket Springs: Individual coils move independently, providing targeted support with better contouring while maintaining firm support where needed.

Construction Quality and Firmness Over Time

Cheap construction causes firmness to change dramatically. Low-density foams compress permanently, creating sags. Poor spring systems develop squeaks and lose support properties. Weak edge support reduces usable sleep surface.

Our Michigan construction uses quality materials and time-tested methods. Our pocket spring systems use quality steel, proper wire gauges, and edge-to-edge coils  for consistent long-term support. We don't cut corners on foam density or use cheap fillers that break down quickly.

Finding Your Perfect Firmness: The Rested Pillow Approach

Choosing the right firmness isn't about picking a number on a scale. It's understanding your body, sleep position, health needs, and finding a mattress that will support you properly for years.

Our Consultation Process

We start with questions, not sales pitches. We want to understand how you currently sleep, any pain issues affecting sleep, sleep position preferences, your partner's needs, previous mattress experiences, and your sleep environment.

This isn't a quick conversation. We take time to understand your situation because the right mattress decision requires proper information.

Education Over Sales Pressure

We focus on helping you understand how firmness works, what to look for in construction quality, and how to evaluate whether a mattress is right for you. We explain why materials feel certain ways, how our construction differs from cheaper alternatives, and what to expect over time.

The Michigan-Made Difference

Making our mattresses in Michigan gives us complete control over materials and construction quality. We use only the best materials, handcraft each mattress one-at-a-time, and we can customize when someone has unique needs.

Our Commitment

We focus on customer satisfaction over quick sales. If you're not happy with your firmness choice, we'll work to make it right; whether that means exchanging for a different firmness as part of our 100 Night Comfort Guarantee, adding a topper, or finding another solution.

We'd rather help you find the perfect mattress from our well-made collection than overwhelm you with dozens of mediocre options. The right mattress firmness truly can change your life, and we're here to help you find it.

Ready to experience the difference? Visit our showroom in St. Joseph, Michigan, or contact us to learn more about our approach to mattress selection.