How thick should my mattress topper be? Sleep experts weigh in

Your mattress topper should be thick enough to cushion your joints and thin enough to slot neatly between your mattress and your fitted sheet. You're looking for a topper that's tall enough to make a difference to the feel of your mattress, but not so tall that you get squashed against the ceiling.

That's all well and good, but when you're shopping for a mattress topper, it helps to have some hard numbers to hand. Most mattress toppers measure somewhere between two and four inches in thickness. That might not sound like a big difference, but those two inches could have a major impact on your sleep quality.

As H&G's resident sleep writer, I've tested enough of the world's best mattress toppers to know that it isn't only the thickness of a mattress topper that matters, but the firmness and the feel. I've identified the optimal topper for front, back, and side sleepers, with help from bedding designers and medical professionals.

How thick should my mattress topper be?

To save you time and money, I've rounded up a few of my favorite mattress toppers at the fairest prices you'll find online. Whether you're looking for a plush topper to soften up an old bed or something firmer to toughen up a sagging mattress, I've got you covered.

What is the point of a mattress topper?

Before we get started, it always helps to define our terms. I asked Byron Golub, Vice President of Product and Merchandising at Saatva, the Smarter Sleep Company, to tell us exactly what a mattress topper is designed to do. 

Byron believes that 'the primary purpose of a mattress topper is to offer additional comfort to the sleeper. Based on the performance benefit you are looking for, toppers can vary in thickness, firmness, and material composition'. 

A nice, thick topper can totally transform the feel of your bed for a fraction of the price of the best mattress. Byron says that 'toppers can be used to make your mattress feel more comfortable. A top-quality topper can prolong the life of an old mattress, reduce motion transfer, and help to regulate temperature if you sleep too hot or cold'.   

Byron knows the difference that one or two inches of foam can make to the fit and feel of your mattress topper. 'Topper thickness and firmness play an essential role in comfortable, quality sleep, especially for sleepers suffering from underlying health conditions,' says Byron. For example, 'thicker toppers on the firmer side will be better for back pain, as they will provide good support and promote proper spinal alignment'. 

Byron Golub

Byron is the Vice President of Product and Merchandising at Saatva. He started out at Saatva as their Senior Product Manager, so he's intimately acquainted with each of their mattress toppers and understands how they might affect your sleep. 

How thick should my mattress topper be?

There's no such thing as a single mattress topper to suit all sleepers. The optimal thickness for your topper will depend on your sleep style, as well as the current condition of your mattress any underlying health conditions. I asked Andrew Buchan, Director at Strictly Beds & Bunks, to tell us more.

Let's start with side sleepers. As Andrew says, 'Side sleeping puts extra pressure on your hips and shoulders. Choosing a thicker topper (around four inches) keeps your spine aligned and prevents those pressure points from becoming a problem.' 

'Back sleepers need a good balance between cushioning and support': Andrew thinks you should 'aim for a topper that's two to three inches thick. This provides comfort without letting you sink so deeply that it throws your spine out of alignment.'

If you sleep on your stomach, then you should consider the firmness of your mattress topper in tandem with the thickness. You're looking for something with medium-firm support to let your chest sink in without enveloping your body. 

It's not all about sleep position. There are a few practical points to bear in mind as you shop for a mattress topper. 'If you suffer from back pain, a topper can help', says Andrew: 'around two inches is usually ideal to improve support without compromising proper spinal alignment. If your mattress is starting to lose its comfort, a thick topper can extend its life. For noticeable improvement on a truly tired bed, opt for a topper between three and four inches thick.' 

Andrew Buchan

Andrew is the founder and director at Strictly Beds & Bunks, the premium bed manufacturer and retailer. Andrew understands the difference that a mattress topper can make to the firmness and feel of a bed and agreed to lend his insights for this review.

You could probably pick up a mattress topper from your local home retailer, but I've found it pays to shop with the specialist sleep stores. That way, you can browse toppers with special features to meet the rest of your sleep needs. You might find a firm topper that incorporates cooling technology or a plush piece that happens to be hypoallergenic. 

What happens if my mattress topper is too thin?

A mattress topper might be more affordable than a brand new bed, but it still isn't cheap. The last thing you need is to spend big money on a mattress topper, only to find out that it's too thin to make an impact. 

I asked Dr. Kevin Lees, D.C., from The Joint Chiropractic, whether a thin mattress topper could alleviate aches and pains. He doesn't think so: 'A thin mattress topper likely won't change the support of the mattress much, though it might be an option if the person is looking for a layer to add breathability. If the idea is to enhance support or add extra cushion for hips and shoulders, shoppers should look for a mattress topper that's at least three inches thick'. 

Dr. Kevin Lees, D.C.

Dr. Kevin is the Director of Chiropractic Operations from The Joint Chiropractic, the nation's largest provider of chiropractic care. He understands how the thickness mattress topper can affect, aggravate, and alleviate back pain. 

What happens if my mattress topper is too thick?

A lot of people think they want a soft mattress. They imagine sinking into plush layers of thick foam and letting the bed swallow them up. If you sleep on your back or stomach, or you simply prefer a firmer surface, this might not be the best idea. 

Bedding designer Parima Ijaz agrees. 'If you are someone who prefers a firmer, more supportive mattress, then a topper that is too thick could actually be more uncomfortable. A topper doesn't consist of springs and framework, the way a mattress does: instead, it is mostly filled with either down, foam, or synthetic fibers, which provide additional plushness. If the topper is too thick, it might struggle to support your body. Staying under four inches with a white goose down filler is most ideal for those who prefer a firmer, more supportive feel.' 

Parima Ijaz

Parima is the founder of Pure Parima, the luxury bedding brand that champions the use of authentic Egyptian cotton. Her father was a bedding developer, so Parima grew up in the textile industry, and drew on her material knowledge for comment in this article.  

Mattress topper FAQs

Is a mattress topper worth it?

I think so, especially as a temporary solution. If you or someone you love is off to college for the first time, they're likely to be faced with a soft, sagging mattress or a super-firm innerspring. The best mattress topper for dorm beds should transform the feel of your bed. If you have a little more cash to spend, and you're likely to stay in the same bed for years to come, then it's worth weighing up the pros and cons of a mattress topper vs new mattress.

Which is the best mattress topper?

For my money, the best mattress topper is the Saatva Graphite Mattress Topper. It hits that sweet spot between comfort and support to suit all sleep styles. Then again, it might not be the best mattress topper for your sleep needs. If you're a hot sleeper, you might appreciate a cooling topper, such as the ViscoSoft Active Cooling Mattress Topper. People who suffer from back pain should consider a memory foam mattress topper: I rate the Coop Retreat Mattress Topper to alleviate aches and pains.

Our verdict

Your mattress topper should be no less than two and no more than four inches thick: exactly where yours should fall within that range depends on your sleep style, the current condition of your mattress, and any underlying health conditions. As a general rule, I'd recommend a thick mattress topper for side sleepers (between three and four inches); a thinner one for stomach sleepers (around two inches); and about three inches for back sleepers. A thicker mattress topper isn't always the answer. Too thick, and your fitted sheet might not fit anymore: then, you'll have to invest in a new set of the best bed sheets.