Best Soft Mattresses

Mattress firmness indicates how the surface of a bed feels beneath the sleeper’s body. The cover and comfort (or topmost) layer of a mattress affects firmness to the greatest extent. At Tuck, we measure mattress firmness using a 1-to-10 scale, with 10 being the firmest and 1 being the least firm — although the vast majority of mattresses sold today fall between a 3 (‘Soft’) and an 8 (‘Firm’).

This page will discuss mattresses that rate as a 4 (‘Medium Soft’) and lower. Soft mattresses are generally most popular among side-sleepers due to improved spinal alignment and pressure relief, as well as lighter individuals who do not experience as much conforming on firmer models. However, softer mattresses have also been linked to certain disadvantages, such as high body heat retention, more off-gassing odor, and shorter overall lifespan.

Who Sleeps Best on Soft Mattresses?

This section will discuss various physiological factors — such as bodyweight and sleep position — that often indicate a sleeper will prefer a softer mattress. But first, a disclaimer: every sleeper is different, and this information applies to most — but not all — mattress owners. We highly recommend testing out a wide range of mattress firmnesses in order to determine your preferred rating before finalizing your purchase.

Let’s begin by talking about bodyweight. For the purposes of this page, the average sleeper weighs between 130 and 230 pounds; ‘below-average weight’ signifies anything less than 130 pounds, and ‘above-average weight’ applies to anything greater than 230 pounds. Bodyweight is one physical factor that generally correlates to firmness: people who weigh less tend to prefer softer mattresses, whereas heavier people often feel most comfortable on a firmer mattress.

Reasons for this correlation include conforming and pressure relief. Mattresses that are softer tend to sink more deeply beneath sleeper’s bodies; in contrast, firmer mattresses will not sink much (if at all) unless the sleeper weighs enough. For this reason, people in the below-average and average weight groups often feel most comfortable on softer mattresses because they can experience the full sinking effects, which can alleviate pressure points along the body, and less comfortable on firmer mattresses that do not sink as much or relieve pressure to the same extent. Alternatively, people in the above-average weight class may sink too deeply into a softer mattress, and this can lead to more pain and pressure. For this reason, heavier individuals tend to feel most comfortable on firmer mattresses. The table below includes the most popular firmness ratings for each of the three weight groups.

Weight GroupMost Commonly Preferred Mattress Firmness
Below-average (Less than 130 Pounds)4 (Medium Soft) and Lower
Average (130 to 230 Pounds)5 (Medium) to 6 (Medium Firm)
Above-average (More than 230 Pounds)7 (Firm) and Higher

Sleep position also affects firmness preferences, since softer mattresses that conform more closely can also improve the sleeper’s spinal alignment. The back-sleeping position naturally aligns the spine on its own, and sleepers who choose this position may not need their mattress to aid spinal alignment. Side-sleepers, on the other hand, sleep in a position that creates an unnatural curvature in the spine. Those who sleep on their side require enhanced support in the neck, shoulders, lower back (lumbar), and hips in order to reduce pain and pressure. For this reason, side-sleepers often prefer Soft or Medium mattresses.

Most stomach-sleepers find soft mattresses somewhat uncomfortable. This is because they sink too deeply, causing them to turn their heads in order to avoid lying face-down on the sleep surface, and this can increase pain and pressure in the neck and shoulders. For heavier people who sleep on their stomachs, a softer mattress can be especially problematic because a high percentage of their weight may be located in their stomach. Stomach-sleepers in the below-average weight group, on the other hand, may feel comfortable on mattresses rated as Medium Soft because they provide some conforming without too much sinking.

The next table lists preferred firmness levels for different sleepers based on bodyweight and sleep position.  

Weight GroupPreferred Firmness for Most Side SleepersPreferred Firmness for Most Back SleepersPreferred Firmness for Most Stomach Sleepers
Below-average (Less than 130 pounds)3 (Soft) to 5 (Medium)4 (Medium Soft) to 6 (Medium Firm)4 (Medium Soft) to 6 (Medium Firm)
Average (130 to 230 Pounds)4 (Medium Soft) to 6 (Medium Firm)5 (Medium) to 7 or 8 (Firm)6 (Medium Firm) to 7 or 8 (Firm)
Above-average (More than 230 Pounds)5 (Medium) to 6 (Medium Firm)6 (Medium Firm) to 7 or 8 (Firm)6 (Medium Firm) to 7 or 8 (Firm)

Common Qualities of Soft Mattresses

Next, let’s discuss some of the different construction and performance factors shared by many mattresses that rate as a 4 or below on the firmness scale.

  • Shorter Lifespan: Softer mattresses often feature more cushioning layers in the comfort system that sag or form indentations. Over time, these can cause sleepers to experience increased pain and pressure.
  • Thickest Mattresses Available: Due to a higher number of layers in the comfort system, softer mattresses tend to be significantly thicker than firmer models — some measuring up to 16″ or higher.
  • Higher Price-point: Mattresses that are softer often feature multiple memory foam and/or latex layers in the comfort system, which can drive up the price. Comparatively, firmer mattresses with fewer comfort system layers are the cheapest options.
  • Conforming and Pressure Relief: Softer mattresses typically offer optimal conforming and pressure relief for people in the below-average and average weight groups because they sink deeply, but not too deeply. Heavier individuals may sink too much, and often prefer Medium to Firm mattresses as a result.
  • Sleeping Hot: Softer mattresses tend to sleep uncomfortably hot for two reasons. One, they sink deeper that firmer mattresses; this can restrict airflow along the surface of the bed and create a body heat trap. Two, mattresses with multiple foam and memory foam layers — which tend to be softer — usually sleep much warmer than firmer models with one or two foam layers. This is due to the body-heat-retaining properties of mattress foam.
  • More Odor: Mattresses emit smells known as off-gassing when they are unpackaged. Most odors dissipate after one to two days, but some may linger and be more unpleasant. Most mattresses associated with long-lasting, unpleasant odors contain polyfoam and/or memory foam, and these are the models that also tend to be the softest.
  • Lack of Responsiveness/Not as Good for Sex: Responsiveness refers to how quickly a mattress responds to the sleeper’s body. Softer mattresses tend to respond the slowest, often due to close conforming — and as a result, they may not be responsive enough for sex compared to Medium/Medium Firm mattresses, which balance responsiveness and softness more effectively.
  • Heavier/Harder to Move: Softer mattresses with more layers in the comfort system are usually heavier than those with fewer layers. As a result, softer mattresses are generally considered harder to move — although this also depends on mattress type, as some models (such as memory foam) are typically lighter than others (such as innersprings) due to the weight and density of their components.

The table below evaluates Soft, Medium/Medium-Firm, and Firm mattresses based on these performance factors:

Performance FactorSoft (4 and Lower)Medium to Medium Firm (5 to 6)Firm (7 and Higher)
LongevityPoor to FairGoodGood to Very Good
ThicknessThickestThickerLeast Thick
Average PriceHighMedium to HighLow to Medium
Conforming/Pressure ReliefFair to GoodVery GoodPoor to Fair
Heat RetentionPoor to FairGoodVery Good
Off-gassingPoor to FairFair to GoodGood to Very Good
SexPoor to FairVery GoodFair
Easy to MovePoor to FairFair to GoodGood to Very Good

Tips for Buying and Maintaining a Soft Mattress

Now that you have determined that a softer mattress is most suitable for your sleep needs and preferences, let’s go over a few tips for buying the right model and maintaining it for years to come.

  • Look for Sleep Trials: Many of today’s mattress manufacturers allow customers to take part in sleep trials. Once a purchase is made, the customer will be able to test out the mattress for a given length of time (usually 90 to 120 nights); if they decide they are not satisfied with the mattress before the trial ends, then they will be able to return the mattress for a full or partial refund — and in some cases, exchange their current mattress for a model with a different firmness rating.
  • Dual Firmness Can Help Couples: Not surprisingly, many couples disagree when it comes to the optimal firmness rating. To accommodate sleep partners with varying preferences, some manufacturers offer mattresses with different firmnesses on each side. While these designs can help both people feel comfortable, it’s important to note that dual-firmness beds can be relatively pricey.
  • Flippable Mattresses Offer Multiple Firmness Options: In addition to dual-firmness models, a small number of mattress makers offer ‘flippable’ mattresses. These designs feature two comfort layers, each with a different firmness rating, and a shared support core. To adjust the firmness, simply flip the mattress over.
  • Understand Warranty Coverage: In most cases, mattress manufacturers list excessive sagging and/or indentations as a defect covered under the product warranty, provided it reaches a certain depth (usually 1″ to 1 1/2″, but sometimes lower). If your softer mattress begins to sag or indent prematurely, then you may be able to have it repaired or replaced at minimal cost to you. However, most warranties also explicitly say that ‘changes in the owner’s firmness preferences’ are not covered under the warranty.
  • Firmness Should Influence Your Pillow Selection: Because sleepers often sink more deeply into softer mattresses, they may not require as much cushioning for their head — and excessive padding can create pain and pressure in the neck and shoulders. For this reason, low-loft (or thinner) pillows are generally recommended for softer mattresses, whereas thicker, high-loft pillows are discouraged.

Conclusion

A softer mattress surface may be your best option if you belong to the below-average or average weight group, or you sleep on your side. If you prefer a firmer mattress, please visit our guide to the Best Firm Mattresses for details. You can also check out our Firmness Guide for more information.