Best thick mattress toppers
Thickness is the number people compare and the material is what decides the outcome.
I earn a commission if you buy through some links on this page. It never changes what I recommend, and I publish negative verdicts on brands I earn from. Editorial independence.
Toppers are sold on centimetres, and depth is a poor predictor of what one does.
A 5 centimetre spacer mesh topper and a 5 centimetre dense foam topper change a mattress completely differently: the mesh takes the edge off a firm surface and the foam envelops you. The material decides how much it softens and how warm it makes you. Thickness mostly decides how much of that you get.
And the rule that governs every topper applies more strongly the thicker it gets: softening and warmth move together. A thick foam topper is the largest change available and the warmest.
A deep topper also creates a practical problem nobody mentions: it breaks your sheets.
The picks
The pick, if you want one answer
Simba Mattress Topper, 7.5 / 10. Substantial cushioning without the heat penalty of deep foam, which is the hardest combination to find at depth.
| Product | Best for | From | Score |
|---|---|---|---|
| Simba Mattress Topper | Best substantial topper | Mid range | 7.5 / 10 |
| Tempur Topper | Biggest change available | Premium | 6.8 / 10 |
| Dormeo Topper | Best deep foam construction | Judge the cash price | 7.2 / 10 |
| Panda Hybrid Bamboo Mattress Topper | Best for clamminess | Mid range | 7.2 / 10 |
Simba Mattress Topper: Best substantial topper
Mid range · 7.5 / 10
The highest scoring topper on this site at 7.5. Micro-springs give depth of cushioning while keeping open structure, so you get the thickness without sealing yourself off from the mattress. That is the combination thickness normally costs you.
Buy it if
You want real cushioning without deep foam's warmth.
Do not buy it if
Your mattress is genuinely too hard. Foam changes more.
Read the full Simba Mattress Topper review
Tempur Topper: Biggest change available
Premium · 6.8 / 10
Scores 6.8, which averages two extremes honestly: ten out of ten for softening and three for temperature. Dense viscoelastic foam conforms completely, which is exactly why it holds heat. Nothing changes a mattress more.
Buy it if
Your mattress is genuinely too hard to sleep on and you do not sleep warm.
Do not buy it if
You sleep hot, or the mattress is only slightly too firm.
Read the full Tempur Topper review
Dormeo Topper: Best deep foam construction
Judge the cash price · 7.2 / 10
Scores 7.2. Foam cut into individual cylinders with open channels between them, which matters more as thickness increases: a thick solid slab has more material to trap heat in. Dormeo lists high against near-permanent discounting, so judge the cash price alone.
Buy it if
You want foam's depth with more air movement than a solid slab.
Do not buy it if
You are buying on the crossed-out price.
Read the full Dormeo Topper review
Panda Hybrid Bamboo Mattress Topper: Best for clamminess
Mid range · 7.2 / 10
Scores 7.2. Good cushioning under a cover that moves moisture. Damp fabric against skin feels warm whatever the air temperature, and a thick topper puts more material between you and the mattress for moisture to sit in.
Buy it if
You want depth and your complaint is dampness rather than heat.
Do not buy it if
You own a hybrid bought for airflow.
Read the full Panda Hybrid Bamboo Mattress Topper review
A thick topper breaks your sheets
Add the two depths together
Standard UK fitted sheets are cut for about 25 centimetres. Modern hybrids run 28 to 35, and a thick topper adds 5 to 10 on top.
A 30 centimetre mattress with an 8 centimetre topper needs a 38 centimetre sheet or deeper, and buy a few centimetres over, because the fabric has to fold under rather than merely reach the edge.
This is also the reliable anchoring solution. A topper is a separate slab sitting loose on a mattress and it moves every time someone gets in or out of bed. A deep fitted sheet sized for both together holds the topper as well as the sheet, which corner straps and grip mats do less well at depth because there is more mass to shift.
Budget for sheets alongside the topper. A thick topper with a short sheet ends up in a cupboard within a fortnight.
Choose the material, then the depth
| Material | Softens | Effect on heat |
|---|---|---|
| Dense viscoelastic foam | Very strongly | Considerably warmer |
| Memory foam | Strongly | Warmer |
| Latex | Moderately, with bounce | Neutral |
| Micro-spring | Moderately, with depth | Neutral to cooling |
| Spacer mesh | Mildly | Coolest |
| Wool | Mildly | Regulates moisture |
Read it as one diagonal. Thickness amplifies whatever the material already does, so a thick foam topper is warmer than a thin one and a thick mesh topper is still cool.
The pairing to avoid at any depth: foam on a hybrid. It sits above the springs and cuts you off from the airflow that was the reason you bought the mattress, and a thick one does it completely.
Depth does not fix a dip
The commonest reason people want a thick topper is a mattress that has gone soft in the middle, and this is the one thing extra thickness does not solve.
Lay a straight edge across the mattress and measure the gap at its deepest point. More than about 25 millimetres and a topper of any thickness follows the dip within weeks, because a topper conforms to whatever is underneath it.
Also measure the slat gaps. Over about 7.5 centimetres and the base is causing the sagging and voiding most guarantees, and plywood costs less than any topper.
And if the mattress is over about seven years old, a thick topper is a meaningful fraction of a decent replacement you will buy anyway. Silentnight's Sleep Now range starts at £169 and Emma's Original Lite is £199 with a three-zone spring layer.
Two other things thickness changes
Bed height. Add the topper to the mattress and the base. Aim for 55 to 65 centimetres floor to the surface you sit on, and a thick topper on a deep mattress on a high divan can push well past that.
Pillow height. A softer surface lets your shoulder sink further, so you need less pillow after fitting a thick topper. Re-run the ten minute test: lie in your sleeping position and have someone check that your neck is a straight continuation of your spine.
What not to buy
A thick topper for a mattress with a dip over 25 millimetres.
Thick foam on a hybrid. The most complete way to cancel a spring layer's airflow.
A thick topper without buying deep sheets. It will be diagonal within a fortnight.
Thickness as a proxy for quality. The material decides what it does.
A thick topper to firm up a soft mattress. Toppers soften; support comes from beneath.
Also considered, and why they are not here
A roundup is only as useful as what it leaves out, so here is what was assessed and rejected for this list.
| Product | Why it is not on the list |
|---|---|
| Silentnight Airmax | Scores 7.4 and is the coolest topper in the category, and spacer mesh softens least, so thickness buys you less here than in foam. |
| Origin Contour | Scores 7. Zoning works in a mattress because it runs through the full support structure; a few centimetres on top cannot restructure how a spine is supported. |
| Mlily Premier Topper | Scores 6.9. Cheap foam softens about as well as dear foam on day one, and what you give up is durability and anchoring. |
| Otty Bamboo Charcoal | Scores 6.7. Competent foam with a charcoal claim that does not survive examination, and foam on an Otty hybrid blocks the airflow that defines the mattress. |
How this list is made, and who made it
Independence
No brand pays to appear on this site and no placement is sold. Some links earn a commission if you buy, which never changes a score, an order or a verdict. Several of the lowest scores here are on products that carry commission, and several recommendations carry none.
Who writes this. Kyle Klinkradt has worked in the mattress and bedding industry for over ten years across retail, distribution and brand partnerships, and has handled, sold or assessed products from every major UK bed-in-a-box brand. Every review on this site is written by one person, so the scores mean the same thing from page to page.
What the assessment is. Construction specifications against what they physically do: spring height and where in the mattress it sits, spring count for the size, gauge, whether the base is sprung or foam, foam density where it is published, comfort layer depth and material. Then the commercial terms that decide what you are actually buying: trial against returns policy, guarantee length against the company's UK trading history at Companies House, and the regulatory record.
What it is not. This is not a laboratory. I do not publish pressure-mapping data or claim to have slept eight years on every mattress here, because nobody has and pages that imply otherwise are not telling you the truth. Where a judgement rests on construction rather than long-term use, the review says so.
What gets a product removed. Leaving the UK market, a specification change that makes the review inaccurate, or a corrected fact. Brands that have withdrawn are kept on the site with the score removed rather than quietly deleted, because people still search for them.
See editorial independence, corrections and the author page.
How these were chosen
Every product here has its own review on this site with a score out of 10, and the score is a judgement rather than an average. Nothing appears in a list because it pays more.
A score is against the market, not against its own range. The cheapest mattress in a lineup is usually priced to make the model above it look reasonable, and the flagship of a budget range has risen into a bracket where better brands compete. Both are judged against what else you could buy for the money.
Everything listed can actually be bought in the UK. That is not a given: Casper withdrew in July 2020 and Leesa no longer sells here, and both still appear in current British roundups with affiliate links attached.
I do not pad the list. Where only three or four products genuinely qualify, there are three or four. A list of seven when the category contains four good ones is a list with three bad recommendations in it.
Prices move constantly. Judge the cash price on the day rather than any percentage beside it. See every review on this site or where the real savings are.
Related guides
Other pages on this site covering the same ground.
- Best wool mattress toppers
- Best super king mattress toppers
- Best soft mattress toppers
- Best small double mattress toppers
Questions people ask
How thick should a mattress topper be?
Choose the material first, because thickness amplifies whatever the material already does. Five centimetres of dense foam changes a mattress far more than 5 centimetres of spacer mesh, and warms you far more too.
Will a thick topper fix a sagging mattress?
No. A topper conforms to whatever is underneath it, so a dip of more than about 25 millimetres reappears through it within weeks whatever the thickness. Lay a straight edge across the mattress and measure the deepest gap.
What sheet do I need for a thick mattress topper?
Add the mattress depth to the topper depth and buy a few centimetres over. A 30 centimetre mattress with an 8 centimetre topper needs a 38 centimetre sheet or deeper, because the fabric has to fold under.
Do I need a different pillow after adding a thick topper?
Often a lower one. A softer surface lets your shoulder sink further, which reduces the gap between your head and the mattress, so you need less pillow height.