How to break in a new mattress (and why it feels firm at first)
Hi, we’re John and Mimi. One of the most common texts we get in the first week is “is it supposed to feel this firm?” Usually the answer is yes, for now. A new mattress and your body both need a little time to get used to each other. Here’s what’s normal, how long it usually takes, and the simple things that help.
The short answer
- Sleep on it every night. Your body heat and movement are what break the foam in. Our listings say you can sleep on a new mattress right away, and that body heat and movement help it recover its shape faster.
- Give it a few weeks. As a rough rule of thumb, most people feel settled in somewhere around two to four weeks. It’s a typical range, not a fixed clock.
- Check what’s underneath. A sagging box spring or wide-gapped slats can make any new mattress feel wrong.
- Don’t stand or jump on it to speed things up. The care instructions on our mattresses say not to.
Why a new mattress feels different
- Fresh foam is at its firmest. New foam usually softens slightly over the first weeks of use, then stays steady.
- It shipped compressed. Our mattresses arrive rolled in a box, and the listings say it may take up to 72 hours to fully recover its original shape. See how long a mattress in a box takes to expand.
- Your body is used to your old bed. If your last mattress had a dip, your back and hips learned to sleep in it. A flat, supportive surface can feel “too firm” for a while even when it’s doing its job.
- Room temperature matters. Memory foam tends to feel softer when it’s warm and firmer in a cool room, so the first chilly nights can feel firmer than the showroom memory in your head.
What to expect in the first month
Every mattress and sleeper is different. This is the typical pattern, not a promise.
| When | What’s normal | What to do |
|---|---|---|
| First 72 hours | It finishes expanding; edges and corners fill out; a light “new” smell fades | Sleep on it, keep the room comfortably warm, open a window |
| First week | Feels firmer than you expected; you may wake up a bit stiff while your body adjusts | Keep sleeping on it every night; check your pillow height |
| Weeks 2–4 | The comfort layers soften a little and the feel evens out | Use the whole surface, not just one spot |
| After a month | This is close to how it will feel day to day | Now judge the feel; text John if something still seems off |
How to help it break in
- Sleep on it every night, and spend some time on it during the day too, like reading or watching TV in bed.
- Use the whole surface. Sit on the edges, sleep in different spots, and move around normally. Kneeling or crawling across it gently is fine; standing and jumping aren’t.
- Keep the room comfortably warm for the first few nights, especially with an all-foam mattress.
- Put it on a proper surface. The setup instructions call for a continuously solid surface, an adjustable base, or slats no more than 2" apart. See what to put under a memory foam mattress.
- Rotate it head to foot. The care instructions say to rotate the mattress for uniform wear. We suggest doing it every few months, and once early on if you always sleep in the same spot.
- Recheck your pillow. A new mattress can change how far your shoulders sink in, so the pillow that worked before may now be too high or too low. See how to choose a pillow.
- Put the protector on from day one. It keeps spills and sweat out of the foam while it settles; the listings say liquid damage doesn’t qualify for a warranty replacement. See do you need a mattress protector.
Still too firm after a month?
- Check the base first. A solid platform feels firmer than an adjustable base or slats. That’s normal, and the mattress isn’t the problem.
- On an adjustable base? Raising the head a little or using zero gravity takes pressure off the hips and shoulders and changes how firm the bed feels. See our zero gravity guide.
- Got a flippable mattress? Our 12" iSwitch and 12" BioPosture iSwitch have a medium firm side and a medium soft side. Flip it and try the other one.
- Think about how you sleep and what you weigh. Side sleepers and lighter people usually like a step softer. Our firmness guide and petite & lightweight sleepers guide explain why.
Feels too soft, or there’s a dip?
A new mattress shouldn’t sag. If you see a dip early on, look underneath first: a worn box spring, a frame with no center support, or slats spaced wider than 2" let the mattress sink where you sleep. Fix the surface and the mattress usually lies flat again. Heavier sleepers who want more push-back should see our best mattress for heavier sleepers guide.
If the surface underneath is solid and you still see a real dent or a flat corner that never filled in, text John a couple of photos with your order number. Defects are covered by the manufacturer’s 10-year limited warranty, and we handle the claim for you. What counts as normal wear is explained in how long a mattress lasts.
Does the type of mattress change anything?
All-foam memory foam mattresses usually change the most in the first weeks, because the whole feel comes from foam. Hybrids rest on pocketed coils that push back right away, so it’s mainly the foam on top that softens. Plush mattresses start soft and change less in feel; firm mattresses are designed to stay supportive, so expect them to soften only slightly. Comparing types? See memory foam vs hybrid.
12" iSwitch Flippable Two Sided Mattress - Medium Firm/Medium Soft - 12ISWITCH
Worried about getting the feel wrong? This one gives you two: sleep on one side, and if it isn’t right, flip it over.
- Two sides: medium firm and medium soft
- Gel memory foam on both sides
- Zip-off machine-washable cooling cover
From $659 (Twin XL) · Queen $769 · See sizes & details
Terry Cloth Mattress Protector - MATPROC1
Put it on the day you unbox the mattress, so the foam stays clean while it breaks in.
- Guards against liquid spills
- Helps guard against dust mites and bed bugs
- Every mattress size
From $31 (Twin) · Queen $34 · See sizes & details
Shop this guide
Still shopping? These are easy to settle into.
- 10" Rose - Medium Firmness - 10BNV, from $279. Medium 10" memory foam with a washable zip-off cover.
- 10" EcoCore Hybrid Premium Soy Foam & Pocket Coil Mattress - Medium Firm, from $499. Medium firm 10" hybrid with edge-to-edge pocketed coils.
- 12" iSwitch Flippable Two Sided Mattress - Medium Firm/Medium Soft - 12ISWITCH, from $659. Two feels in one: flip it to change.
Questions we hear a lot
How long does it take to break in a new mattress?
As a rough rule of thumb, most people feel settled in somewhere around two to four weeks of sleeping on it every night. A mattress that shipped in a box may take up to 72 hours to fully recover its shape first, and you can sleep on it right away.
Why does my new mattress feel so firm?
New foam is at its firmest and usually softens slightly over the first weeks. Your body may also be used to the dip in an old mattress, and memory foam feels firmer in a cool room. Sleep on it every night and keep the room comfortably warm for the first few nights.
How can I break in a mattress faster?
Sleep on it every night, spend time on it during the day, use the whole surface instead of one spot, and keep the room comfortably warm. Do not stand or jump on it; the care instructions on our mattresses say not to.
Should I rotate a new mattress?
Yes. The care instructions on our mattresses say to rotate it for uniform wear. We suggest turning it head to foot every few months, and once early on if you always sleep in the same spot.
What if my new mattress has a dip or still feels wrong after a month?
Check what it sits on first: a worn box spring, a frame without center support, or slats more than 2 inches apart can make a mattress sink. If the surface is solid and you still see a dent, text John photos and your order number at 818-924-3744. Defects are covered by the 10-year limited warranty and we handle the claim.
Not sure if it’s normal? Just ask us
Text John what you’re feeling, how many nights you’ve slept on it, and what it sits on. He’ll tell you honestly whether it’s just break-in or something to look at. Text or call 818-924-3744, 6 AM to 9 PM Pacific. Still choosing? Start with our how to choose a mattress checklist. See our Purchase Policy & Warranty for the details.
Written by John & Mimi Venti, MimiJohn. Expansion, rotation and care wording from the product listings on this site; break-in times are typical, not guaranteed. General guidance, not medical advice.