Firm vs. Medium Mattress
By Sarah Anderson, Certified Sleep Science Coach 
Is a firm bed best to sleep on for a healthy back, or should you choose the balanced feel of a medium mattress? If this question or a similar one has flashed through your mind, then you probably want to know how you can determine if a mattress is right for you without having to try it out directly. After all, the wrong mattress can leave you stiff and sore the next day.
Firm and medium mattresses are each suited for different kinds of sleepers, though there is a little overlap when it comes to back sleepers. Before we detail what kind of sleepers each is suitable for, we should first discuss mattress firmness levels.
What are Firmness Levels?
Firmness levels express how a mattress is likely to feel when most people lie down. They’re often subjective because a person’s body type can change how a mattress feels to them.
For example, a firm mattress may feel a touch soft to a person over 230 pounds because they press down enough to soften the bed’s surface. Conversely, a medium mattress may feel too firm for a smaller person because they do not press down enough to soften the mattress and help it conform to their body.
Firmness levels are determined by the firmness scale—a 1-10 scale where 1 is the softest and 10 the firmness. However, some companies may reverse this and have 1 as the hardest option and 10 as the softest.
Why are firmness levels important? Every sleep style has a firmness range uniquely suited for it. A person’s sleep style is determined by their favorite sleep position and body weight.
Here’s a quick overview of what each sleeping style needs:
- A mattress for side sleepers should fall into the soft to medium range. This ensures the bed provides enough pressure relief.
- A mattress for back sleepers should offer a medium-firm to firm feel. This promotes a neutral spine alignment. Medium feels are acceptable if the mattress features lumbar support.
- A mattress for stomach sleepers should have a firm feel to limit sinkage. If the mattress is too soft, it can misalign a stomach sleeper’s spine.
- A mattress for combination sleepers should have a medium feel. A responsive mattress surface also keeps a person from feeling stuck as they move.
- A mattress for petite sleepers should be on the softer end of the firmness range for their preferred sleep position.
- A mattress for heavy sleepers should be on the firmer end of the recommended range for their favorite sleep position.
About Firm Mattresses
Firm mattresses usually fall between an 8 to a 10 on the traditional firmness scale. Their surface is stable with little give and sinkage. Firm beds lift a sleeper and keep them on top of the mattress.
Who Are They Suitable For?
Firm mattresses are often recommended for stomach and back sleepers because they limit sinkage that can misalign the spine. When the spine shifts out of its neutral alignment by bowing too far into the mattress, it causes back pain.
People over 230 pounds may also find a firm mattress surprisingly comfortable. They remain steady under their body and often feel softer to a heavier person than the average sleeper.
Hot sleepers may also wish to choose a firm mattress because they retain less body heat than a softer bed. Firm mattresses conform less to a sleeper. This means they have less contact with the body and absorb less heat. The reduced malleability also increases airflow around a sleeper’s body.
Finally, firm mattresses are a good choice for sleepers who want to lie on top of their mattress instead of sinking into their bed.
About Medium Mattresses
Medium mattresses usually fall between a 5 or 6 on the firmness scale. They have a well-rounded feel with an even mix of support and cushion. Medium mattresses avoid feeling too soft by allowing a person to sink into the mattress and feel unsupported. Yet, they are also not so firm that a sleeper will wake up with aches and pains.
Usually, they’re quick to react when a person lies down and moves across the surface.
Who Are They Suitable For?
Medium mattresses may provide comfort to the widest range of sleepers, thanks to their balanced feel.
They’re popular with side sleepers who want a pressure-relieving bed that feels supportive instead of soft. Medium mattresses are also great for combination sleepers because they provide adequate support for every position.
Couples with differing sleep styles often compromise by choosing a medium mattress. For example, a back sleeper and a side sleeper can comfortably share a medium bed.
Heavier sleepers may want to be cautious when sleeping on a medium mattress. It’s not uncommon for their bodies to sink too far into the mattress, misaligning their spines and causing back pain.
Speaking of back pain, some sleepers find that a medium mattress worsens chronic back pain. If you’re a back pain sufferer, try a medium-firm mattress instead. Research suggests it’s the best firmness for alleviating and preventing back pain.
Other Firmnesses to Consider
Firm and medium mattresses aren’t the only beds worth a look. Depending on your sleep style, you may be better off with a medium-firm, medium-soft, or soft mattress.
Medium-Firm
If you’re shopping for the best mattress for back pain, it’s difficult to do better than a medium-firm mattress. Research suggests it’s the optimal firmness to prevent and relieve back pain.
Medium-firm mattresses are a good choice for back sleepers, stomach sleepers, and select combination sleepers. They’re also a good choice for hot sleepers, couples, and people over 230 pounds.
Medium-Soft
Medium soft mattresses offer some extra cushioning yet maintain a supportive feeling. They’re also a good choice for budget shoppers who want a plush mattress since truly soft beds often carry high price tags due to their thick comfort layers.
Medium-soft mattresses are excellent for side sleepers and people under 130 pounds.
Soft
A soft mattress typically has thick, plush comfort layers to cushion a sleeper’s body to relieve pressure. A high-quality soft mattress will have extra support features to keep a person from sinking too far into their mattress.
Soft mattresses are well-suited for side sleepers who want a bed they sink into for a cradling feel. Lightweight individuals usually appreciate the pressure relief a soft mattress offers.
If you want to learn more about soft and firm mattresses, check out our plush vs. firm mattress guide.
Types of Mattresses
Once you’ve decided what firmness you want, you should consider what type of mattress is best for you. Most people choose between one of four types—memory foam, latex, innerspring, and hybrid mattresses.
Memory Foam
A memory foam mattress has a top-to-bottom design. Typically they consist of a comfort layer, a transition layer, and a supportive base. Inexpensive models may leave out the transition layer to save on production costs.
Traditional memory foam tends to retain body heat. However, many manufacturers create excellent cooling mattresses by infusing their memory foam with gels or another conductive material.
Memory foam mattresses come in all firmness levels, giving sleepers the freedom to choose a bed right for their needs. They are also available at a wide range of potential prices. Budget shoppers should be pleased to know that many excellent memory foam mattresses cost under $1000.
Latex
Latex mattresses have a conforming feel similar to memory foam mattresses. For more information about the differences between memory foam and latex mattresses, read our memory foam vs. latex mattress guide.
The typical drawback of a latex mattress is its high price tag. Many latex beds cost between $1000 to $2000. Eco-friendly shoppers might consider the price worthwhile, but bargain hunters may want to look at another type of mattress.
Innerspring
A traditional innerspring mattress has a simple design, with a set of coils encased in fabric and thin layers of padding on the top and bottom. This design allows sleepers to flip and rotate their beds.
Innerspring mattresses promote a firm sleeping surface, with many owners complaining about morning soreness from insufficient pressure relief. Usually, they’re ranked as medium-firm to firm. This is why we recommend hybrid mattresses for side sleepers interested in a bouncy bed.
Hybrid
Hybrid mattresses essentially have an innerspring base and a top layer of conforming foam. By combining these elements, mattress manufacturers cut down on the drawbacks of innerspring and memory foam mattresses.
Still, hybrids come with their own set of drawbacks. Shoppers often pass on a hybrid mattress because the mattress is more costly than an innerspring or memory foam bed. Others look for a more lightweight mattress to make rotating the bed and changing the sheets easier.
Take Advantage of Sleep Trials!
With so many mattress firmnesses to choose from, it may feel a bit intimidating to pick one right for you. Many mattress companies helpfully include a trial period with their mattress, keeping customers from ending up with the wrong mattress for their sleep style. Sleep trials usually last a few months, so you have plenty of time to decide if a mattress feels good.
However, even if you choose a mattress with a sleep trial, it’s still important to know what firmness range is right for you before you buy.
Are you considering an online mattress you can’t try before you buy? Customer reviews are a helpful way to get an idea of how a bed feels.
Frequently Asked Questions
How do I know if my mattress is too firm?
Your mattress is likely too firm for you if you regularly wake up with neck or back pain. Too-firm mattresses typically can’t relieve pressure points, allowing them to build up into pain. In particular, side sleepers may wake up with sore shoulders and hips if their mattress is too firm.
Should side sleepers have a firm or soft mattress?
Side sleepers need the pressure-relieving cushion that comes with a softer mattress. Firm beds often allow pressure to build up in a side sleeper’s shoulders and hips. This leaves a side sleeper stiff and sore when they wake. A side sleeper’s mattress should have a soft, medium-soft, or medium feel.
How can I make my mattress more comfortable?
If your mattress is too firm, a mattress topper is usually the best way to give it a plush feeling. Soft bedding can also help alter its feel.
If your bed is too soft, you can make your mattress firmer by using a mattress topper or moving your mattress to a firmer foundation.
Other tips for a comfortable mattress:
- Investing in the best pillows promotes a good night’s sleep.
- Breathable bedding is a must if you’re a hot sleeper or live in a warm climate.
- You can try rotating your mattress regularly to maintain its supportive feel.
Do foam mattresses get softer over time?
Yes, there’s an initial break-in period for a foam mattress. Often, it takes a week or two to break in a foam mattress fully. Typically, this break-in period is followed by a subtle softening over the years as a mattress ages.
Alternatively, a foam mattress’s soft comfort layer may grow firmer as the bed wears out. This usually happens when regular use flattens the bed’s top layer.
What is the best month to buy a mattress?
May is often recommended as the best time of year to buy a mattress. Many new mattress models are launched during the summer months. So, retailers try to clear out old stock in May to make room. In particular, Memorial Day is one of the year’s biggest mattress sales days.
Other great times of the year to shop for a new mattress include:
Is a Firm or Medium Mattress Right For You?
Choosing the right mattress requires an understanding of your sleeping style. Firm mattresses are well-suited for stomach and back sleepers. Medium mattresses provide a balanced feel excellent for side, back, and combination sleepers.
If you feel overwhelmed by your choices, remember a sleep trial ensures you can return an unsuitable mattress.
This article is for informational purposes and should not replace advice from your doctor or other medical professional.
Sarah Anderson, Certified Sleep Science Coach
Sarah Anderson is a sleep, health, and wellness writer and product reviewer. She has written articles on changing and improving your sleep schedule, choosing the right mattress for chronic pain conditions, and finding the best pillow for you. Sarah Anderson has her Bachelor of Arts degree from Arizona State University in Journalism and Mass Communications. Prior to working for Zoma, she wrote for a variety of news publications. Sarah's work has been featured on Bustle, PureWow, and other publications.
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