5cm vs 10cm Mattress Topper: How Thick Should Yours Be?

Choosing between a 5cm and 10cm mattress topper mainly comes down to how much you want to change the feel of the mattress underneath. A 5cm topper adds a lighter layer of cushioning without adding too much extra height, while a 10cm topper creates a deeper, fuller and more noticeable comfort layer. Neither thickness is automatically better for everyone. Your existing mattress, preferred bed height, fitted sheet depth and the amount of cushioning you want should all influence the decision.

5cm vs 10cm Mattress Topper: Quick Comparison

You can compare both options across our full Mattress Toppers collection.

How Thick Should a Mattress Topper Be?

There is no single mattress topper thickness that is right for every bed. The more useful question is how much you want the topper to change the feel of your current mattress.

If your mattress is still comfortable and supportive but you want a little extra softness on the surface, a 5cm mattress topper may be enough. If you want a much more noticeable cushioning layer, a 10cm mattress topper is likely to suit you better.

Thickness is only one part of the decision. The filling, construction and condition of the mattress underneath also affect how the finished bed feels. A thicker topper does not automatically mean that it will be right for every sleeper or every mattress.

When Is a 5cm Mattress Topper a Good Choice?

A 5cm mattress topper is a practical choice when you want to make a moderate change to your sleeping surface without adding a very deep layer to the bed.

It may suit you if your mattress still feels supportive but you would prefer a slightly softer and more cushioned surface. Because it has less depth than the 10cm option, it can also be easier to lift, move and refit when changing your bedding.

A 5cm topper can work particularly well for guest rooms, spare beds and bedrooms where you want additional comfort without substantially increasing the overall height of the mattress.

A 5cm topper may be the better option if:

• Your mattress is already reasonably comfortable.
• You want a lighter cushioning layer.
• You do not want to add too much height to the bed.
• You want something easier to handle when changing bedding.
• You are refreshing a guest bed or spare room.

When Is a 10cm Mattress Topper a Better Choice?

A 10cm mattress topper is designed for people who want a more noticeable change to the feel of their bed. The deeper filling creates a fuller cushioning layer between you and the mattress underneath.

This can be particularly useful when your mattress still provides adequate underlying support but the surface feels firmer or flatter than you prefer. Compared with a 5cm topper, the 10cm option creates a more substantial comfort layer and gives the bed a fuller appearance.

A 10cm topper may be the better option if:

• You want deeper cushioning.
• Your existing mattress feels firmer than you prefer.
• You want a more noticeable comfort upgrade.
• You like a fuller, more generously cushioned bed.
• You are comfortable with the additional bed height.

Stoftly mattress toppers are available in both thickness options through our Mattress Topper range.

Is a Thicker Mattress Topper Always Better?

No. A thicker mattress topper is not automatically better.

A 10cm topper provides a deeper comfort layer, but some sleepers may prefer the lighter feel of a 5cm topper. Your mattress also plays an important role. If the mattress underneath already feels comfortable, adding substantially more depth may be unnecessary.

It is better to choose according to the change you want to make:

• Small comfort adjustment: consider 5cm.
• More noticeable cushioning: consider 10cm.

You should also consider the extra height, fitted sheet depth and ease of handling before choosing the thicker option.

Which Thickness Is Better for a Firm Mattress?

If your mattress feels firmer than you would like, a 10cm topper will generally create a more noticeable layer of cushioning than a 5cm topper. The additional filling places a deeper comfort layer over the existing mattress surface.

A 5cm topper can still make a difference when the mattress only needs a modest adjustment. If the bed feels generally comfortable but slightly too firm on top, the thinner option may be sufficient.

It is important to distinguish between surface firmness and a mattress that has lost its underlying support. A mattress topper can alter how the top of a mattress feels, but it cannot rebuild the internal structure of a damaged mattress.

Can a Mattress Topper Help an Older Mattress?

A mattress topper can help refresh the surface of an older mattress when the mattress underneath is still reasonably supportive. Adding another layer can make the sleeping surface feel softer, smoother and more cushioned.

However, a topper is not a substitute for a mattress that is heavily sagging, damaged or no longer providing adequate support. Adding a thick topper over significant dips or structural problems does not repair the mattress underneath.

If the mattress remains supportive but simply feels tired or firmer than you would like, a topper can be a practical way to adjust its comfort before considering replacement.

Does a Thicker Mattress Topper Sleep Warmer?

Not necessarily. A 10cm topper contains a deeper cushioning layer than a 5cm topper, but thickness alone does not determine how warm a bed will feel.

The filling material, topper construction, duvet, sheets, room temperature and your own sleeping preferences can all influence temperature during the night. For that reason, we would not recommend choosing 5cm or 10cm based on thickness alone if sleeping temperature is your main concern.

Choose primarily according to how much cushioning and additional bed height you want.

Mattress Topper Thickness and Fitted Sheet Depth

One practical difference between 5cm and 10cm toppers is the amount of height they add to the bed. This matters when choosing a fitted sheet.

Once a topper is placed on your mattress, your fitted sheet needs enough depth to comfortably accommodate the combined mattress and topper.

For example, if you already have a deep mattress and then add a 10cm topper, a standard fitted sheet may no longer provide enough depth to sit securely underneath the mattress.

Before choosing your sheet, measure from the bottom of the mattress to the top of the topper. You can then compare that measurement with the pocket depth of the fitted sheet.

For more help, read our fitted sheet size and depth guide or browse our Fitted Sheets collection.

Should a Mattress Topper Be the Same Size as the Mattress?

Yes. In normal use, your mattress topper should correspond to the size of the mattress underneath it.

For example, use a Double topper on a Double mattress and a King Size topper on a King Size mattress. Buying a larger topper does not create better cushioning and can result in excess material extending beyond the mattress edges.

Stoftly mattress toppers are available in popular UK sizes:

• Single
• Small Double / 4ft
• Double
• King Size
• Super King

If you already know your bed size, you can browse our Single Mattress Topper, Small Double Mattress Topper, Double Mattress Topper, King Size Mattress Topper and Super King Mattress Topper options.

5cm vs 10cm Mattress Topper: Which Should You Choose?

For most people, the decision comes down to the amount of cushioning they want rather than simply choosing the thickest topper available.

Choose a 5cm mattress topper if your existing mattress is still comfortable and supportive and you want a lighter comfort adjustment with less additional height.

Choose a 10cm mattress topper if you want a deeper and more substantial cushioning layer, particularly when the surface of your mattress feels firmer than you prefer.

If you are still unsure, consider these three questions:

1. How much do I want to change the feel of my current mattress?
2. How much additional bed height am I comfortable adding?
3. Will my current fitted sheets accommodate the mattress and topper together?

Answering those three questions will usually make the choice between 5cm and 10cm much easier.

Explore both thicknesses, colours and UK bed sizes in our Mattress Toppers collection.