Best cot mattresses 2024: Which? Best Buys and expert buying advice

Our expert advice and reviews will help parents choose the best cot mattress for their baby. 

This means a product that's comfortable yet supportive and safe, able to cope with the inevitable leaks that will happen as your baby grows, and one that will last for as long as you need it.

We explain what you should look out for when buying the best cot mattress for your baby, including the best brands to go for, what size and thickness of cot mattress you need, the different materials a cot mattress can be made from, and how to dispose of a cot mattress once you've finished using it.

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The best cot mattresses 2024

Our impartial lab tests have uncovered the very best on the market, and we’ve selected our top picks. All of them have performed well in our body support, durability and safety tests, so you can be sure you are buying the best.

Table last updated December 2023.

Join Which? to get access to all our Best Buys and cot mattress reviews. We’ve tested more than 40 cot mattresses from brands including John Lewis, Mamas & Papas and Ikea, but only the very best make a Best Buy.

The best cot mattress brands

As well as our tests, we also ask parents how happy they are with their chosen brand, so we can give you some insight into the best out there along with the ones to avoid.

Our tests have uncovered a sizeable difference in the best and worst. The best-scoring brand in our tests has an average score of 79%, whereas the worst brand scores, on average, 16%. 

Have a look at the results for the biggest brands. 

Only logged-in Which? members can view the results in the table below. If you're not yet a member, join Which? to get instant access.

Avoid a cot mattress that's unsafe, is unsupportive for your baby, or lacks durability by reading our guide on what makes a Don't Buy cot mattress.

Video: how to buy the best cot mattress

Want to know how we sort the wheat from the chaff? Learn more about how we test cot mattresses.

Types of cot mattress

Foam cot mattress

Generally speaking, foam cot mattresses are the least expensive type. They're usually just a piece of high-density foam with a wipe-clean, waterproof PVC cover. Some will come with two sides: a cotton side and a wipe-clean side. 

Some foam mattresses have ventilation holes, but these aren't a necessity, and you might also see hypoallergenic foam mattresses advertised. 

Pros Generally easy to keep clean, can provide good support and resistance to denting, and foam is relatively light so will be easy for you to move or turn over.

Cons Some parents don't like the idea of the basic, all-PVC-covered mattress because of concerns about clamminess, foam mattresses with ventilation holes can be harder to keep clean if your baby is sick because residue can gather in the holes and mesh, and thin foam may lose its shape and dent easily.

Spring or pocket spring cot mattress

A simple spring mattress is made of springs secured into a rigid frame. These are then surrounded by layers of foam and fabric. 

Pocket spring mattresses are the most expensive type. These are made of coiled springs, each sewn into their own individual pocket. 

Unlike a regular spring mattress, each spring in a pocket spring mattress can move independently of the others, so the mattress is deemed to be more comfortable and give better support. These springs are, like regular spring mattresses, covered by layers of foam and fabric. 

Spring cot mattresses often have a cotton cover on one side and wipe-clean material on the other side. 

Pros Many parents like the familiarity of a traditional spring mattress, and while the wipe-clean side is the recommended surface for your baby to sleep on, you can flip it on to the cotton side if it's hot and your baby feels clammy. 

Cons More expensive than foam mattresses with pocket spring cot mattresses being the priciest, the cotton side may be preferred for comfort, but can be more difficult to keep clean.

Coir or natural fibre cot mattress 

These have a core of coconut fibre with other layers of different materials. The fibres are coated in latex for strength and protection, and the natural fibre filling helps air circulate through it. This type is available with a wipe-clean covering. 

Pros One of the firmest types of mattress and they tend to last longer because they hold their shape well, so could be a sensible buy if you want to use it for more than one child. 

Cons Less widely available than foam or spring interior and can be more expensive than the alternatives.

Hollow frame (PurFlo) cot mattress

This type of hollow frame mattress is only made by PurFlo. It's advertised as the only fully breathable, fully washable cot mattress and is basically a mesh-covered frame. 

Pros The whole mattress is washable and as it's hollow it provides good air circulation for your baby.

Cons More expensive than most other cot mattresses, and as it's 15cm deep you'll need to keep your cot or cot bed on its lowest setting to ensure that you have a decent enough gap from the mattress to the top of the cot or cot bed's rail.

Hypoallergenic cot mattress

These have a quilted top layer that can be easily detached from the body of the mattress, so you can wash it at (ideally at 60°C) to kill any dust mites that may cause allergies. 

Pros Easy to keep clean.

Cons Can be more expensive than other kinds of mattress.

Travel cot mattress

A travel cot is a collapsible cot that can be folded down and stored in a bag, making it ideal for taking on holiday or when visiting family members. 

A travel cot mattress should be no more than 10cm thick and you should expect the mattress in a crib or Moses basket to be no more than 5cm thick. These thicknesses are specified in BS 1877: Part 10:1997, the cot mattress safety regulations.

Pros Easily transported, can be folded down, quick to set up

Cons May not last as long as a cot or cot bed, can be heavy to carry and bulky even when folded

How to buy the best travel cot – our advice will help you find a travel cot that provides a comfortable and safe space for your baby, that's straightforward to use and easily transportable too

How much does a good cot mattress cost? 

The prices of cot mattresses range anywhere from about £35 to £250.

But price and quality don't necessarily go hand in hand, as our cheapest Best Buy costs £60, while our most expensive Don’t Buy is more than £200.

Quality and safety don't always go up with price, either, so it's worth looking at this before the price.

What is a Which? Great Value cot mattress?

We award a Great Value logo to cot mattresses that are at least 20% cheaper than the average typical price for a cot mattress and score at least 60%. 

However, a Great Value cot mattress also has to be safe, so we only choose ones that get a minimum of three stars for safety and are tested to the latest version of the cot mattress safety standard (2021).

See all our Great Value cot mattresses. 

What is the standard cot mattress size in the UK?

140 x 70cm is the standard size of most UK cot beds, so you need to buy one with these dimensions. This will ensure that the mattress fits snugly into the frame, leaving no gaps around the edge.

Another typical size is 120 x 60cm. If you buy a cot that's smaller or larger than this, you can get mattresses specially made to fit, but this will cost more.

You need to make sure the mattress fits your cot or cot bed frame snugly. A gap bigger than 3cm (1.2in) is a potential hazard for your baby as their arms, legs or head could get trapped in the gap.

Not all mattresses come in the same standard size, but your cot or cot bed should specify which size it requires. 

How thick should a cot mattress be?

We recommend that your baby's cot mattress is at least 10cm thick. Your baby’s weight will be concentrated on a small area of the mattress, and you don't want their body sagging through and hitting the base underneath.

Best cot bed brands and expert buying advice: we've quizzed parents on big-name brands, including Ikea, John Lewis and Mamas & Papas, to uncover the most popular 

Should babies sleep on a firm or soft mattress?

Babies need to sleep on a mattress that's firm and flat with a waterproof cover to help keep it clean and dry. You can assess the firmness and flatness by pressing your hand firmly on the centre and edges. There should be some resistance and it should bounce back immediately.

In our cot mattress tests, we assess the support it will provide for your baby. Our experts measure body support before putting it through a durability test that simulates two to three years of regular use.

We then measure the body support after these tests to see how the mattress will hold up, so you know it's going to still be doing a great job of keeping your baby comfortable over time. 

What about reversible cot mattresses? 

Many mattresses (mainly of the spring and pocket spring varieties) are made to be reversible. Each side of the mattress will be specially designed to accommodate the needs of your rapidly growing baby.

That's because a cot bed mattress might be used for five or six years, during which time your baby will more than triple in weight. Because of this, manufacturers often design cot bed mattresses with one side specifically for babies and the other for toddlers or children.

Typically, one side will have springs and foam designed to be sturdy, but gentle for a baby to sleep on for the first 12 months. The reverse side will have sturdier material to cope with a growing toddler.

The mattress should clearly indicate which side is suitable for what age group. 

Cot mattress and bedding safety – our expert advice on getting the safest sleeping products for your child

Can I use a second-hand cot mattress for my baby?

We generally don't recommend you buy or use a second-hand cot mattress. The Lullaby Trust (the safer sleep charity) states there is some research that has found an increased chance of sudden infant death syndrome (SIDS) when using a second-hand mattress brought in from outside of the family home, although the link is not yet proven.

If you're using a second-hand cot mattress, inspect it before your baby starts using it, ensuring that it's in good condition, with no rips or tears. The mattress should still be firm and springy when you push your hand down on it, and there should be no dips or indentations.

Ideally, the mattress will have a removable cover, which can be washed at 60°C to remove any bacteria.

See all our cot mattresses reviews. 

How should you dispose of your cot bed mattress?

We don't recommend buying a second-hand cot mattress. Which? tests have demonstrated that mattresses can lose up to a quarter of their firmness in just a few years of use, so it's best to get rid of the mattress once your baby is no longer using it.

Much like a full-size mattress, they're not always the easiest to dispose of, as they won't be picked up by your general council rubbish collection. Luckily, as they're smaller, they tend to fit in a car more easily, so you should be able to take the cot mattress down to your local tip.

Some cot mattress brands, such as Kub, offer a mattress collection and recycling scheme, but this is a rare occurrence for cot mattress manufacturers. It's also possible to organise a mattress collection from a professional recycling firm, but you'll have to pay for this service.

Alternatively, if you're particularly creative and can create a frame to go round it, you could try converting your baby's cot mattress into a dog bed (best for larger dogs).

Where to buy a cot mattress

Cot mattresses are available to buy from a range of retailers including:

• John Lewis sells own-brand mattresses that typically cost between £18 to £95 as well as other brands such as Boori, Silver Cross and Snuz.
• Argos stocks Cuggl models (the Argos own brand) which typically cost £25 to £85, as well as popular adult mattress brands such as Silent Night.
• Mamas & Papas has a wide range of own-brand models on its site costing £22 to £229, but it also stocks Snuz and Gaia.
• Smyth's Toys has a reasonable selection of cot and cot bed mattresses from the brand Baby Elegance, which cost around £25 to £80.
• Ikea sells its own branded cot mattresses in both 140 x 70cm and 120 x 60cm dimensions. Prices range from £35 to £159.