A mattress that feels wrong is often new, cold, or sitting on the wrong base, and those problems are fixable before you think about replacing it. An uncomfortable night doesn't automatically mean you've bought the wrong mattress.
Fixing a too soft or too firm mattress in brief
Give a new mattress at least 30 nights to settle before judging its feel. If it's too firm, check the room isn't cold, as memory foam firms up in the cold, then add a topper if needed. If it's too soft or sagging, check the base first and rotate the mattress head to foot; a 2 to 4cm dip is normal settlement. If nothing helps, it may be the wrong mattress for you.
Give a new mattress at least 30 nights to settle
A new mattress needs regular use before you can judge its feel, so sleep on it for at least 30 nights. Dreams' troubleshooting guide explains that it often won't feel like it did in the shop at first: the fillings, especially memory foam, need to soften and contour to your body.1 Its guide to getting used to a new mattress puts the usual adjustment period at two to six weeks.2 A disappointing first night is too soon to decide.
Most mattresses soften slightly with use, especially through their foam and fibre layers, but significant softening takes time. Don't count on a dramatic change: Dreams notes that some mattresses with a very high spring count or a dense foam core won't soften enough for lighter sleepers. I'd give it time without expecting it to become a completely different mattress.
How does your mattress feel?
- Too firm
- Too soft or sagging
If it feels too firm, use it more and then add a topper
Spend some waking time on the bed while it settles. TEMPUR's instructions for use recommend resting, reading or watching TV in bed during the break-in period, as the movement helps the foam cells open.3 That's a simple thing to try before buying anything extra. A rigid, solid base can make a mattress feel firmer too.
If it still feels too firm after the adjustment period, add a topper. Mattress toppers add a cushioning layer to relieve pressure points without changing the mattress's core support. If you're choosing again, compare soft mattresses, not another firm one with a topper on top.
A topper softens a firm mattress but won't fix a sagging one
The extra cushioning sits on top, so a topper can't restore support your mattress has lost. If your mattress feels too soft or has a dip, check the base and whether the dip is normal settlement before spending money on a topper. For cleaning and upkeep, follow the topper maker's care instructions.
A topper adds cushioning on top, but on a sagging mattress it sinks into the same dip.
Memory foam feels firmer in a cold room
A warmer room can change how your foam mattress feels. Dreams says memory foam is temperature sensitive: it feels firmer in a cold room and softer in a warmer one. For its own foam, TEMPUR puts the firmer feel at 18 C or less and says the warmer the room, the softer it feels. Judge a foam mattress at a room temperature you find comfortable before deciding it's too firm.
If it feels too soft, check the base before the mattress
An unsupportive base can make your mattress feel softer than it should. Widely spaced slats, a dipping base and always sleeping in the same spot can all cause deep sagging. It's worth finding out which you're dealing with before paying for a replacement.
Measure the gap under a broom handle on the bed, then on the floor. If the dip shrinks on the floor, the base is the likely problem.
- Measure the dip. Lay a broom handle across the mattress where it dips and measure the gap beneath it.
- Measure on the floor. Put the mattress on the floor and measure the gap again in the same place.
- Read the result. If the dip shrinks or disappears on the floor, the base is likely to be the problem rather than the mattress.
- Rotate and spread out. Follow the care guide's rotation schedule, or rotate every season, and use the whole sleeping surface rather than always settling into the same spot.
If the base is the problem, compare replacement bed frames before spending money on another mattress.
Questions people ask about a too soft or too firm mattress
Will a firm mattress soften over time?
A firm mattress will usually soften slightly, especially through its foam and fibre layers. Significant softening takes time, so don't expect a dramatic change in feel after a few nights. Dreams notes that some mattresses with very high spring counts or dense foam cores won't soften enough for lighter sleepers. If you're a lighter sleeper, allow for that limit when deciding whether to keep it.
Can a topper fix a mattress that's too soft?
No, a topper won't fix a mattress that's too soft. It adds cushioning but can't restore the support underneath you. Check the base and whether any dip goes beyond normal settlement before spending money on another layer that could leave you with the same problem.
When should I replace the mattress instead?
Replace it if the base is sound and it still doesn't suit you after settling, or it sags beyond normal settlement. Use the mattress replacement checker to help you decide whether replacement makes sense. If you're buying again, mattresses with a sleep trial let you try the feel at home. If you'd like a firmer feel next time, compare firm mattresses.
