How to Choose a Mattress Topper: UK Buying Guide
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Choosing the right mattress topper comes down to four main factors: how your mattress currently feels, how much cushioning you want, the topper material and the correct size for your bed. A thinner topper generally makes a more subtle change to the sleep surface, while a deeper topper creates a more noticeable comfort layer.
A mattress topper can be useful when a mattress is still structurally sound but feels firmer, flatter or less comfortable than you would like. It is not, however, a substitute for replacing a mattress that is badly sagging, damaged or no longer providing suitable support.
This guide explains how to choose a mattress topper in the UK, including thickness, materials, sleeping position, bed size and the situations where a topper may or may not be useful.
What does a mattress topper do?
A mattress topper sits on top of your mattress to change the feel of the sleeping surface. Depending on its thickness and construction, it can add cushioning, softness or a different surface feel without requiring you to replace the entire mattress.
A topper is therefore most useful when you are generally satisfied with the underlying mattress but want to alter the comfort layer above it.
For example, you might consider one if:
- your mattress feels firmer than you prefer;
- you want an additional cushioned layer;
- you want to refresh the surface feel of an older but still usable mattress;
- you want a deeper, softer-feeling sleep surface; or
- you want to adjust comfort without immediately buying a new mattress.
How do you choose a mattress topper?
Start with the problem you are trying to solve rather than choosing a topper purely by price or thickness.
Consider these five questions:
- Does your mattress feel too firm, too soft or simply less comfortable than you want?
- Do you want a subtle change or a noticeably deeper cushioned layer?
- Which topper material gives you the type of feel you prefer?
- Does the topper match the dimensions of your mattress?
- Is the mattress itself still in good enough condition for a topper to make sense?
There is no single mattress topper that is best for every sleeper. The right choice depends on the mattress underneath it and the type of surface feel you want to create.
Should a mattress topper be the same size as the mattress?
Yes. A mattress topper should normally match the length and width of the mattress underneath it.
A topper that is substantially smaller may leave uncovered areas around the edges, while one that is too large may not sit neatly on the mattress.
For UK beds, common mattress dimensions are:
| UK Bed Size | Typical Mattress Dimensions |
|---|---|
| Single | 90 × 190 cm |
| Small Double | 120 × 190 cm |
| Double | 135 × 190 cm |
| King | 150 × 200 cm |
| Super King | 180 × 200 cm |
Check the actual measurements of your mattress before ordering, particularly if you are unsure of the bed size or are using a non-standard mattress.
What thickness mattress topper should you choose?
The thicker the topper, the more noticeable the additional comfort layer is likely to feel. Thickness alone does not determine comfort, because filling density, construction and material also matter, but it is an important starting point.
| Topper Depth | Generally Best For |
|---|---|
| Thinner topper | A more subtle adjustment to the existing mattress feel |
| Around 5cm | Extra cushioning without creating a particularly deep new layer |
| Around 10cm | A deeper and more noticeable cushioned surface |
If thickness is your main deciding factor, read our detailed 5cm vs 10cm mattress topper guide, where we compare the two depths in more detail.
Is a 5cm or 10cm mattress topper better?
A 5cm mattress topper is better when you want a lighter adjustment to your existing mattress, while a 10cm topper is better when you want a deeper and more noticeable cushioned layer. Neither thickness is automatically better for everyone.
| If you want... | Consider | Why |
|---|---|---|
| A subtle change to mattress comfort | 5cm topper | Adds cushioning without creating a particularly deep new layer |
| Extra softness over a mattress that feels slightly firm | 5cm topper | Provides an additional comfort layer while retaining more of the mattress feel underneath |
| A deeper, more padded sleep surface | 10cm topper | Creates a more substantial layer between you and the mattress |
| A more noticeable change over a firm-feeling mattress | 10cm topper | The additional depth creates a more pronounced cushioned surface |
Thickness is only one factor. The topper material, filling, construction and condition of the mattress underneath also affect how the bed feels.
A deeper topper also increases the overall height of your bed, so check that your fitted sheet has enough depth to fit securely over the mattress and topper together.
For a more detailed comparison, read our 5cm vs 10cm mattress topper guide.
Which mattress topper material is best?
There is no single best mattress topper material for everyone. The right choice depends on whether you want a soft padded feel, closer contouring, a more responsive surface or a particular type of fibre construction.
Rather than choosing by material name alone, start with the type of comfort you want from your existing mattress.
| If you want... | Consider | Why |
|---|---|---|
| A soft, padded comfort layer | Hollowfibre | Fibre filling creates a cushioned surface without the closely contouring feel associated with foam |
| A surface that conforms more closely around the body | Memory foam | Foam responds to pressure and creates a more contouring feel |
| A more responsive, springier surface feel | Latex | Latex typically feels more responsive than memory foam, although firmness varies between products |
| A fibre-filled topper made from natural materials | Wool or other natural fibres | These provide a different fibre construction, with feel and care requirements depending on the individual product |
Material is only one part of the decision. Thickness, filling amount, construction, firmness and the condition of the mattress underneath can all affect how a topper feels in use.
The Stoftly Mattress Topper uses soft hollowfibre filling with quilted construction, so it is intended for shoppers looking for an additional padded and cushioned layer rather than a memory foam-style contouring surface.
Hollowfibre vs memory foam mattress toppers
Choose hollowfibre if you prefer a softer, padded and fibre-filled comfort layer; choose memory foam if you prefer a more closely contouring surface that responds to pressure. The better option depends on the type of feel you want rather than one material being universally superior.
| Feature | Hollowfibre | Memory Foam |
|---|---|---|
| Typical feel | Soft, padded and cushioned | Closer-contouring and pressure-responsive |
| How it changes the bed | Adds a fibre-filled comfort layer over the mattress | Creates a more conforming layer around the body |
| Best suited to | Shoppers who prefer a softer, fuller bedding-like feel | Shoppers who prefer a more moulded, foam-based feel |
| What else to check | Thickness, filling amount, quilting and attachment method | Foam density, firmness, thickness and product construction |
Material alone does not determine whether a topper will feel comfortable. Two hollowfibre toppers or two memory foam toppers can feel very different depending on their depth, filling, firmness and overall construction.
The Stoftly Mattress Topper uses soft hollowfibre filling with quilted construction and elasticated corner straps. It is designed to add a padded comfort layer rather than the closely contouring feel associated with memory foam.
What mattress topper should you choose if your mattress feels too firm?
If your mattress is still supportive but feels firmer than you prefer, choose a topper based on how much additional cushioning you want rather than simply choosing the thickest option available.
| If your mattress feels... | Consider | Why |
|---|---|---|
| Slightly firmer than you prefer | A lighter comfort layer, such as around 5cm | Can add softness while keeping more of the original mattress feel |
| Noticeably too firm | A deeper comfort layer, such as around 10cm | Creates a more substantial cushioned surface above the mattress |
| Firm but otherwise flat and supportive | A soft hollowfibre topper may be suitable | It can add a padded surface without changing the mattress structure underneath |
| Uneven, sagging or structurally damaged | Investigate the mattress itself | A topper cannot repair the underlying support problem |
Thickness and material both matter. A deeper topper generally creates a more noticeable change, while a soft fibre-filled construction such as hollowfibre provides a different surface feel from firmer foam or latex options.
If your main question is how much depth to choose, see our 5cm vs 10cm mattress topper guide.
Can a mattress topper make a bed firmer?
Yes, but only if the topper itself is designed to create a firmer surface. A soft or heavily cushioned topper will usually make the bed feel softer rather than firmer.
If your mattress feels too soft, focus on the topper's material, firmness and density rather than thickness alone.
| If your bed feels... | What to consider |
|---|---|
| Slightly softer than you prefer | A firmer topper may change the surface feel |
| Very soft but still structurally sound | Look for a topper specifically designed with a firmer feel |
| Soft because the mattress has sagged or lost support | Investigate the mattress itself rather than relying on a topper |
A thicker topper is not automatically a firmer topper. A thick hollowfibre topper, for example, is generally intended to add cushioning rather than create a hard or extra-firm surface.
The Stoftly Mattress Topper is designed as a soft hollowfibre comfort layer, so it is more suitable for adding cushioning than for making an already soft mattress significantly firmer.
What should side sleepers look for in a mattress topper?
Side sleepers usually need to consider how much surface cushioning they want around areas such as the shoulders and hips while still maintaining suitable support from the mattress underneath.
The right amount is individual. Consider:
- how firm the existing mattress feels;
- whether you prefer a softer or more supportive surface;
- the topper thickness;
- the material and construction; and
- your overall comfort rather than sleeping position alone.
A side sleeper on a very firm mattress may prefer more surface cushioning than someone whose mattress is already relatively soft.
Can a mattress topper help with back pain?
A mattress topper can change how the surface of a mattress feels, but it should not be treated as a medical treatment for back pain.
If discomfort is mainly caused by a mattress feeling firmer or less cushioned than you prefer, changing the surface layer may alter how comfortable the bed feels.
However, persistent back pain can have many causes, and a topper cannot diagnose or treat a medical condition. It also cannot repair a mattress that has lost its structural support.
If back pain is persistent, severe or worsening, seek appropriate medical advice rather than relying on a bedding product alone.
What are the benefits of a mattress topper?
A mattress topper can be useful because it allows you to change the sleeping surface without replacing the mattress immediately.
Potential practical benefits include:
- adding an extra cushioned layer;
- making a firm-feeling mattress feel softer at the surface;
- altering the comfort of an otherwise usable mattress;
- giving you a choice of different materials and depths; and
- providing an easier way to experiment with surface comfort than buying a new mattress.
The amount of difference you notice will depend on the mattress underneath and the topper you choose.
What are the disadvantages of mattress toppers?
A topper is not suitable for every mattress or every comfort problem.
Possible drawbacks include:
- adding extra height to the bed;
- requiring deeper fitted sheets;
- moving if the topper is not secured properly;
- changing how warm or cushioned the bed feels depending on the material;
- not fixing structural mattress problems; and
- creating an unwanted feel if you choose the wrong firmness or thickness.
This is why choosing by your actual comfort requirement is more useful than simply buying the thickest topper available.
Are mattress toppers worth it?
A mattress topper can be worth considering when your mattress is still supportive and usable but you want to change its surface comfort.
It is less likely to be a good solution when the mattress is badly sagging, damaged, uneven or no longer providing suitable underlying support.
A simple rule is:
- Comfort problem: a topper may be worth considering.
- Structural mattress problem: investigate the mattress itself rather than expecting a topper to repair it.
Can a mattress topper fix a sagging mattress?
No. A mattress topper cannot repair a sagging mattress or restore the support structure inside it. A topper changes the comfort layer above the mattress, so any significant dip or uneven area underneath will still remain.
Do you need a topper or a new mattress?
| What you notice | What to consider |
|---|---|
| Mattress is flat and supportive but feels too firm | A softer mattress topper may add useful surface cushioning |
| Mattress is comfortable but feels less cushioned than you would like | A topper may help change the surface feel |
| Visible permanent dips or body impressions | Investigate the mattress itself rather than relying on a topper |
| Uneven, damaged or structurally unsupportive mattress | A topper will not repair the underlying problem |
If the mattress is still structurally sound but simply feels firmer than you prefer, the next question is how much additional cushioning you want. Our 5cm vs 10cm mattress topper guide explains the difference between a lighter and deeper comfort layer.
Mattress topper vs mattress protector: what is the difference?
A mattress topper changes comfort; a mattress protector primarily protects the mattress.
| Product | Main Purpose |
|---|---|
| Mattress topper | Adds or changes the comfort layer above the mattress |
| Mattress protector | Provides a protective layer between the mattress and bedding |
They can also be used together. If you want to understand protector types and when one may be useful, read our UK mattress protector guide.
Where does a mattress topper go on the bed?
A topper sits directly on top of the mattress and underneath your fitted sheet.
If you also use a mattress protector, check the fit and depth of your bedding. Depending on the protector style, it may sit over both the topper and mattress so the layers are held together beneath the fitted sheet.
The important point is that everything should fit securely without compressing or distorting the topper.
What should you look for when buying a mattress topper?
Before buying, check:
- Size: match the topper to the mattress dimensions.
- Thickness: decide how noticeable you want the additional layer to be.
- Material: compare fibre-filled, foam, latex and other constructions according to the feel you prefer.
- Current mattress condition: make sure the mattress itself is still suitable for use.
- Attachment method: elastic straps or other fixing methods can help keep a topper positioned on the mattress.
- Care instructions: check the manufacturer's washing and maintenance guidance.
- Sheet depth: make sure your fitted sheet can accommodate the combined mattress and topper height.
Choosing between a 5cm and 10cm Stoftly Mattress Topper
The Stoftly Mattress Topper uses soft hollowfibre filling with quilted construction and elasticated corner straps to help keep it positioned on the mattress.
It is available in 5cm and 10cm depth options, allowing you to choose between a lighter additional comfort layer and a deeper cushioned surface.
If your main priority is deciding between those two depths, see our full 5cm vs 10cm mattress topper comparison.
You can also browse our wider mattress topper collection for the currently available sizes and options.
Final thoughts
The best mattress topper for you is the one that addresses the specific way you want your current mattress to feel.
Start by checking whether the mattress itself is still in good condition. Then choose the topper according to the amount of cushioning you want, the material you prefer, the correct mattress size and how substantial a change you want to make.
If you only want a lighter adjustment, a thinner topper may be enough. If you want a deeper comfort layer over a firm-feeling mattress, a thicker topper may be more appropriate.
Most importantly, treat a topper as a way to change the surface comfort of a usable mattress, not as a way to repair a mattress with structural problems.