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How to Make Your Soft Mattress More Firm

If your new mattress lacks the support you need, try these tips before buying another one.

Mercey Livingston CNET Contributor
Mercey Livingston is a health and wellness writer and certified Integrative Nutrition Health Coach. She's written about fitness and wellness for Well+Good, Women's Health, Business Insider, and Prevention.com among others. When not writing, she enjoys reading and trying out workout classes all over New York City.
Mercey Livingston
3 min read
A woman lies across a mattress, thinking

If your new mattress is too soft, you don't have to buy a new one to fix the problem.

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Do you feel like you can relate to Goldilocks when it comes to finding the right mattress? You don't want one that's too firm, and a mattress that's too soft can be just as uncomfortable. Unless you're a strict side sleeper, mattresses that are too soft can misalign the spine and promote lower back pain, which is a recipe for sleep disaster.  

If you've found yourself with a new mattress that's too soft, or an old mattress that's softened up over time, there are several things you can do (inexpensively) to tailor your mattress to fit your needs. Keep reading for ideas you can try to make your soft mattress firmer and more supportive.

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Try a mattress topper

A hand presses down on a latex mattress topper

A latex mattress topper can help your soft bed feel more supportive.

Sleep On Latex

You may be familiar with plush mattress toppers that make your bed feel even softer, but there are plenty of mattress toppers that can do just the opposite. When it comes to choosing a topper that will make your bed firmer, you can generally find options made of memory foam, latex or polyurethane

You'll want to look for a topper that's 2 inches or more thick. You can also check the ILD (impression load deflection) if you're shopping for a latex topper. The ILD tells you how firm the mattress topper feels. The higher the number, the denser and firmer it will feel. Take a look at our best mattress toppers for a list of our favorite firm options. 

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Give it a solid surface

A wood slat foundation for a mattress

A wood slat foundation is one type of support that can make your mattress feel firmer.


The first thing you can consider changing for a firmer mattress is the support structure. Do you have it on a box spring? If so, consider the age and shape of the box spring. If it's older and not as sturdy as it once was, this can cause the mattress to feel less supportive. 

Also if you have a more modern mattress, you may need to ditch the box spring altogether, since many manufacturers recommend using a flatter and more solid surface to support the foam mattress' weight. This goes for your Casper mattressNectar mattressBrooklyn Bedding mattress and so on. 

Some other types of platforms you could try are a slat foundation, platform bed or another foundation that's stable and solid and provides a more even surface than a bouncier box spring. 

You can also try placing a piece of plywood in between the bed foundation and the mattress, according to Nectar Sleep. This may be especially helpful with a foam mattress since they need a sturdier foundation.

Turn down the thermostat in your bedroom

Temperature reading of 68 on a Nest thermostat
Tyler Lizenby/CNET

If you have a foam mattress and normally sleep in a warmer room, one thing you can try is cooling down the room. The cooler temperature can make your foam mattress feel firmer, since heat can soften the density of the foam. It'll also help you sleep a bit better.

Keep in mind that your body heat will also affect it some, but it can't hurt to try turning down the thermostat to see if it makes a difference for your mattress. Try cooling down your room at least a few hours before bed so that the room and mattress have enough time to cool down. 

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.