Choosing a firm vs soft memory foam mattress is not simply a choice between a hard block and a soft block. Memory foam is normally the upper comfort layer, while the support foam beneath it has a major effect on stability and firmness. Body weight, sleeping position, bed base and personal preference change how the same construction feels.
A soft feeling surface can still have supportive foam underneath, and a firm mattress can still contain a contouring memory foam layer. This guide explains how to compare the complete construction and choose a feel that matches your preference rather than relying on a label alone.
This guide explains the practical differences between soft, medium and firm mattresses. It also compares the current All Foam range so you can see how memory foam depth, support grade and total mattress depth work together.
The quick answer
Choose a softer feel when you want more noticeable cushioning and are comfortable settling further into the sleeping surface.
Choose a medium feel when you want a balance between surface cushioning and a stable support layer.
Choose a firm feel when you prefer less sink, a steadier surface and a stronger sense of support from the foam base.
These descriptions help narrow the choice, but they do not replace a comparison of the layers inside the mattress. A mattress with a thick memory foam comfort layer can still have a firm overall feel when it sits above a substantial high density or Reflex support base.
What mattress firmness actually means
Mattress firmness describes the overall feel when you lie on the sleeping surface. It is influenced by how quickly the upper layers compress, how deeply your body settles and how strongly the support base resists further compression.
A softer mattress normally allows more immediate surface cushioning. A medium mattress usually offers a more balanced response. A firm mattress generally permits less sink and feels more stable beneath the body.
Firmness is not the same as quality. A soft mattress is not automatically less durable, and a firm mattress is not automatically better made. Quality depends on the materials, construction, cover, support base and whether the product is suitable for its intended use.
Firmness is also not the same as support. Support describes how the complete mattress carries the body and maintains a stable sleeping surface. A mattress can feel cushioned at the top while still having a firm support base underneath. This combination is common in layered memory foam mattresses.
Why the same mattress feels different to different people
Mattress descriptions are useful, but no label can account for every person. Body weight, sleeping position, body shape, bed base and previous mattress experience all affect the result.
Someone moving from a very soft mattress may describe a medium model as firm. Someone replacing a hard and worn sleeping surface may find the same medium mattress noticeably more cushioned.
Your first impression can also be shaped by the mattress you have used for several years. A familiar surface often becomes the reference point, even when it has softened or lost support over time. Before ordering, decide whether you want the new mattress to feel softer, similar or firmer than the one you use now.
This relative comparison is often more useful than trying to choose a firmness word without any reference point.
How body weight affects mattress feel
Body weight changes how much force is placed on the comfort and support layers. A lighter person may compress the upper foam less and remain closer to the surface. A heavier person may settle further into the same material and engage more of the support base underneath.
This does not mean every lighter sleeper needs a soft mattress or every heavier sleeper needs a firm one. Personal preference still matters. It means that the same mattress can feel different because each person compresses the foam to a different degree.
When comparing mattresses, think about how much surface cushioning you usually enjoy. If you dislike feeling enclosed by the mattress, a firmer construction may suit your preference. If you value a more noticeable contouring sensation, a medium construction or a deeper comfort layer may feel more suitable.
For a shared bed, consider both sleepers rather than choosing for only one person. When preferences differ, a balanced medium option is often the first model worth comparing, but the final decision should still reflect which compromise both people can live with comfortably.
How sleeping position affects the choice
Sleeping position changes which parts of the body place the most pressure on the surface. This can influence how much cushioning or stability feels comfortable. Front sleepers can compare the dedicated foam mattress for front sleepers guide, while back sleepers can use the separate foam mattress for back sleepers guide.
Side sleeping
Side sleepers place more concentrated contact through the shoulder and hip area. Some prefer more surface cushioning so these areas can settle into the upper layers. A mattress that feels too firm may not provide the amount of contouring they expect.
This does not mean every side sleeper should choose the softest available mattress. The support base still needs to feel stable, and body weight affects how deeply the comfort layer compresses. A medium mattress can be a practical starting point when a balanced feel is preferred.
Back sleeping
Back sleepers often look for a surface that combines contouring with a stable base. Too much sink may feel less steady, while a very hard surface may not provide the preferred amount of cushioning.
Medium and firm mattresses can both suit this preference depending on body weight and how much surface give the sleeper enjoys. The full layer build is more informative than the firmness label alone.
Front sleeping
Front sleepers often prefer a surface that does not allow excessive sink through the centre of the body. A firmer construction may feel more stable for this position, particularly when the sleeper dislikes a deep contouring sensation.
Comfort remains personal, so this should be treated as a practical comparison point rather than a strict rule.
Changing position during the night
Many people do not remain in one position. If you regularly change between side and back sleeping, a balanced medium feel may provide a useful compromise. If you move frequently and dislike the slower response associated with deeper memory foam, pay attention to the support foam and total construction, not only the upper comfort layer.
Soft mattresses
A soft mattress creates more immediate cushioning and normally allows greater surface compression. This can appeal to customers who enjoy a plush feel and a more noticeable sense of settling into the mattress.
Softness can come from the comfort layer, the support foam or both. A thick soft upper layer placed over a firmer base may feel cushioned at first while remaining more stable deeper in the construction. A mattress built with softer foam throughout may allow more overall compression.
The main question is whether the level of sink feels comfortable and controlled. A mattress that is too soft for the user can feel difficult to move on or less stable than preferred. The issue is not that softness is inherently wrong. It is that the surface and base need to match the sleeper and the intended use.
The current standard All Foam mattress range begins with a medium model rather than a soft model. Customers who want to design a different layered feel can review the custom foam mattress builder, which offers a choice of support grades, memory foam comfort layers and total depths.
Medium mattresses
A medium mattress aims to balance cushioning and support. It generally allows more surface give than a firm model while maintaining a steadier feel than a soft construction.
This makes medium firmness a common starting point for customers who do not want either extreme. It can also be useful for shared beds when both sleepers need a reasonable compromise, although individual body weight and preference still affect the experience.
The Deep Sleeper Comfort is the medium option in the current All Foam range. It contains an Air Tech ventilation pad, 2 inches of quality memory foam and 6 inches of medium density support foam. The finished mattress is 20cm deep.
The medium density base gives this model a more accommodating feel than the high density base used in Deep Sleeper Back Care. The 2 inch memory foam layer provides contouring at the surface without being as deep as the 3 inch comfort layer used in the firmer models.
Choose this mattress when you want a balanced medium feel, prefer the shallowest standard construction in the range and do not want the stronger support sensation of the high firm options.
Firm mattresses
A firm mattress allows less overall compression and provides a more stable surface. Customers who dislike a deep sinking sensation often prefer this type of feel.
Firmness can come from a higher support grade, a deeper support base or a combination of both. The comfort layer still matters. A firm mattress with memory foam near the surface can provide contouring without feeling soft throughout the entire construction.
The Deep Sleeper Back Care is the firmest standard option by its stated firmness. It contains an Air Tech ventilation pad, 3 inches of quality memory foam and 6 inches of high density support foam. The finished depth is 22.5cm.
Compared with Deep Sleeper Comfort, it has an extra inch of memory foam and replaces the medium density base with high density support foam. This gives the surface a deeper comfort layer while the base provides a firmer and more stable foundation.
The product name should not be treated as a medical promise. Choose it because you prefer its high firmness, high density base and deeper memory foam layer, not because you expect a mattress to diagnose, prevent or treat a health condition.
High firm and deeper constructions
A high firm mattress usually combines a substantial support base with a firm overall feel. It may also use a deeper construction to provide more material beneath the sleeper.
The Luxury Deep Sleeper is the deepest mattress in the All Foam range. It contains an Air Tech ventilation pad, 3 inches of quality memory foam and 7 inches of Luxury Reflex support foam. Its total depth is 25cm including the cover.
The memory foam depth matches Deep Sleeper Back Care, but the support base is one inch deeper and uses Luxury Reflex foam. Reflex foam has a faster recovery feel than memory foam, so it provides a responsive support layer beneath the slower contouring material at the surface.
Choose this mattress when you want the deepest standard construction, a high firm feel and a more substantial support base. Check the finished bed height before ordering because a 25cm mattress can noticeably raise the sleeping surface.
Firmness and support are not the same thing
This distinction is one of the most important parts of choosing a mattress.
Firmness is the sensation you notice when lying on the surface. Support comes from how the complete construction carries the body. A mattress can have a cushioned upper layer and a firm support base. It can also feel firm at the surface while using a shallower construction.
The three All Foam mattresses show this clearly.
Deep Sleeper Comfort uses 2 inches of memory foam above 6 inches of medium density foam.
Deep Sleeper Back Care uses 3 inches of memory foam above 6 inches of high density foam.
Luxury Deep Sleeper uses 3 inches of memory foam above 7 inches of Luxury Reflex foam.
The amount of memory foam does not determine firmness by itself. Deep Sleeper Back Care and Luxury Deep Sleeper both use 3 inches of memory foam, yet their support materials and total depths differ. Deep Sleeper Comfort uses less memory foam, but its medium density base gives it the medium classification.
The Memory Foam Mattress Buying Guide explains how comfort layers, support bases, total depth, covers and bed bases should be compared together.
Consider how easy the mattress feels to move on
Memory foam responds more gradually than many standard support foams. A deeper memory foam layer can create a more noticeable contouring sensation. Some people enjoy this close response, while others prefer a surface that recovers more quickly when they change position.
If easy movement is important to you, compare the upper memory foam depth and the material underneath it. A responsive support base can help the mattress feel steadier beneath the comfort layer, but the surface will still retain the slower response associated with memory foam.
A firmer mattress does not always mean a quicker surface response. The comfort material still affects how the top of the mattress behaves. This is another reason to read the full construction instead of choosing from the firmness label alone.
Think about temperature and ventilation
Some sleepers naturally feel warmer than others. Mattress construction, room temperature, bedding, covers and personal preference all influence sleeping temperature.
Every mattress in the All Foam range includes an Air Tech ventilation pad and Heat Dispersion Technology in the listed key details. Each model also has a quilted zip off cover.
These features are part of the construction, but no mattress can control every factor that affects temperature. Heavy bedding, waterproof protectors, bedroom ventilation and seasonal conditions can all change the result. For a fuller temperature check, read Does Memory Foam Make You Hot?.
When comparing firmness, do not assume that a firm mattress will automatically feel cooler or that a softer mattress will always feel warmer. The materials near the surface and the bedding used above them matter more than the firmness word on its own.
Check the bed base before changing firmness
A mattress rests on the structure beneath it. A damaged or uneven base can affect how the mattress feels and may make a new product seem softer, firmer or less stable than intended.
Inspect the frame, divan or slats before ordering. Look for broken slats, bowed sections, unsupported gaps and loose fittings. The supporting surface should be level and appropriate for a foam mattress.
A slatted base may be suitable when it provides even support and the gaps are not too wide. Check the bed manufacturer guidance when you are uncertain.
Do not use a firmer mattress as a way to hide a damaged base. The underlying problem should be corrected first so the new mattress has consistent support across its full width and length.
Choose for both sleepers in a shared bed
Couples often have different ideas of comfort. One person may prefer more cushioning, while the other values a firmer and more stable feel.
Start by comparing the mattress each person uses now. Identify what each sleeper wants to change. A useful discussion is not simply soft versus firm. It should cover sink, movement, surface cushioning, ease of changing position and finished bed height.
When preferences are close, the medium Deep Sleeper Comfort may offer the most balanced starting point. When both sleepers prefer less sink, Deep Sleeper Back Care or Luxury Deep Sleeper may be more suitable comparisons.
When preferences differ greatly, a standard single firmness mattress may require compromise. The custom mattress builder allows different layer combinations, but the available online builder creates one construction across the full mattress rather than separate firmness zones for each side. Contact All Foam before ordering if your requirement falls outside the listed options.
Decide whether you need a mattress or a topper
A mattress topper changes the upper comfort layer of an existing mattress. It can add cushioning or create a firmer surface feel when the mattress underneath remains structurally sound.
A topper cannot repair a damaged support core, broken springs, deep sagging or an uneven bed base. If the mattress has lost its structure, adding another layer above it will not correct the underlying fault.
The mattress topper range includes memory foam, medium density foam, high density foam and Reflex options. These products can be useful when the existing mattress is still supportive but the surface feel needs adjustment.
The Mattress Topper or New Mattress guide explains how to assess the existing mattress before deciding which purchase is appropriate.
Use a topper carefully when adjusting firmness
A softer topper can add cushioning to a mattress that feels too firm. A firmer foam topper can change the surface response of a mattress that feels too soft. The final result still depends on the support underneath.
A thin topper creates a lighter change. A deeper topper has a greater influence on the surface feel and raises the total bed height more noticeably.
Do not expect a topper to transform every mattress. A very soft or damaged mattress may continue to allow excessive sink because the weak structure remains below the topper. A very hard mattress may still influence the overall feel beneath a shallow comfort layer.
Choose a topper only after confirming that the existing mattress and bed base remain stable.
Measure the bed and check finished height
The standard All Foam mattress sizes are Single at 90cm by 190cm, Double at 135cm by 190cm, King Size at 150cm by 198cm and Super King at 180cm by 198cm.
Measure the usable area of the bed frame or divan rather than relying only on the name of the existing mattress. Older frames and imported furniture may not match current standard UK dimensions.
Check the width and length in more than one place. If the frame has raised sides or corner fittings, measure the narrowest internal points.
Also compare mattress depth. Deep Sleeper Comfort is 20cm, Deep Sleeper Back Care is 22.5cm and Luxury Deep Sleeper is 25cm including the cover. The deeper models raise the sleeping surface and may change how much of the headboard remains visible.
When a custom mattress may be more suitable
The standard range provides three clear constructions, but some customers already know the exact foam grades and layer order they want.
The custom foam mattress builder supports standard UK sizes, total depths of 8, 9 or 10 inches, one to three layers and a choice of six foam grades. The available materials are Medium, High, Severe Very Firm, Reflex Medium, Reflex Grey and Memory Foam.
Use the builder when the standard mattress constructions do not match your preferred combination. A common approach is to choose a supportive lower layer and add memory foam or another grade above it for comfort.
The builder prices only valid combinations. It does not replace the need to decide what feel you want, and it does not create split firmness across the two sides of a double mattress.
Common mistakes when choosing firmness
Choosing only from the product name
A name can describe the intended feel, but it does not show the full layer construction. Read the memory foam depth, support grade and total depth before deciding.
Assuming firmer always means better support
A mattress needs an appropriate support structure, but the hardest available surface is not automatically the best choice for every person. Comfort preference and body weight influence the result.
Ignoring the current mattress
Your existing mattress provides the most useful reference point. Decide what feels wrong about it and what you want the replacement to change.
Treating a topper as a structural repair
A topper adjusts surface feel. It cannot repair sagging, broken components or an uneven base.
Forgetting the bed base
A damaged base can change how any mattress feels. Inspect it before placing the new mattress on top.
Using firmness as a medical decision
Mattress firmness is a comfort and construction choice. Product names and general descriptions should not be treated as medical advice or guarantees of symptom relief.
Assuming every medium mattress feels the same
Different comfort materials, support grades and depths can produce very different results even when two products share the same general label.
A simple way to make the decision
First, describe your current mattress. Decide whether it feels too soft, too firm, uneven, worn or simply uncomfortable at the surface.
Second, decide how much sink you prefer. Think about whether you enjoy a close contouring feel or want to remain nearer the surface.
Third, consider body weight and sleeping position. These affect how deeply the mattress compresses and where cushioning is most noticeable.
Fourth, compare the complete layer build. Look at memory foam depth, support material and total mattress depth.
Fifth, inspect the bed base and measure the available space.
Sixth, decide whether the existing mattress is structurally sound. If it is, a topper may provide the adjustment you need. If it is not, compare replacement mattresses.
Seventh, choose the closest All Foam construction. Deep Sleeper Comfort provides the medium option. Deep Sleeper Back Care provides the high firmness option. Luxury Deep Sleeper provides the deepest high firm construction.
Which All Foam mattress should you choose
Choose Deep Sleeper Comfort when you want a medium feel, 2 inches of memory foam, a medium density support base and a total depth of 20cm.
Choose Deep Sleeper Back Care when you prefer a high firmness, 3 inches of memory foam, a high density support base and a total depth of 22.5cm.
Choose Luxury Deep Sleeper when you want the deepest standard construction, 3 inches of memory foam, 7 inches of Luxury Reflex support foam and a total depth of 25cm including the cover.
All three models are made in the UK, include a quilted zip off cover and are available in Single, Double, King Size and Super King.
The Foam Mattress vs Spring Mattress guide can help when you are still deciding which type of support system to buy.
Frequently asked questions
Is a firm mattress always more supportive
No. Firmness describes surface feel, while support depends on the complete construction. A cushioned mattress can still have a substantial support base underneath it.
Is a medium mattress suitable for everyone
No single firmness suits everyone. A medium mattress can provide a balanced starting point, but body weight, sleeping position and personal preference affect how it feels.
Do heavier sleepers always need a firm mattress
Not always. Higher body weight normally compresses the foam more deeply, but comfort preference remains personal. Compare the support base, comfort layer and total depth rather than following one general rule.
Which All Foam mattress has the softest feel
Deep Sleeper Comfort is the medium and most accommodating standard option. The current standard range does not include a mattress labelled soft.
Which All Foam mattress is firmest
Deep Sleeper Back Care carries the High firmness description. Luxury Deep Sleeper is described as Luxury High Firm and provides the deepest, most substantial construction. Compare both layer builds to decide which type of firm feel you prefer.
Can a mattress topper make a firm mattress softer
A suitable topper can add cushioning when the mattress underneath remains structurally sound. The thickness and material determine how noticeable the change will be.
Can a firm topper repair a soft mattress
A firm topper may change the surface feel, but it cannot repair a worn or sagging support core. Replace the mattress when the underlying structure has failed.
Does mattress depth determine firmness
No. Depth affects how much material is present, but the foam grades and layer order determine how the construction responds. Two mattresses of similar depth can feel very different.
Should a layered memory foam mattress be turned over
A layered mattress has a designated sleeping surface and should not normally be turned upside down. Follow the supplied care guidance and rotate it when recommended.
What should I do when two sleepers prefer different firmness levels
Compare where the preferences overlap and identify which features matter most to each person. A medium model may offer a compromise when the difference is small. Contact All Foam before ordering when the required construction is not covered by the standard options.
