Your baby deserves a comfortable and safe night's sleep. But as our tough tests prove, opting for a well-known brand doesn't guarantee you'll get a safe and supportive cot mattress.
Our independent reviews can help you choose the best cot mattress for your baby, but we also ask parents about whether they're happy with their purchase and which brands they would recommend to a friend.
So whether you've got your eye on a cot mattress from John Lewis, or you'd prefer to buy from Ikea, first find out the brands parents really rate, and what our testing has uncovered about them.
In February 2021 we asked 1,878 parents which brand of cot mattress they owned.
A total of 24 brands were identified, with the following five being the ones most parents owned:
But whilst these brands are the most popular, when we asked parents how satisfied they were with them, and if they would recommend that brand to a friend, the feedback was varied.
One of the most popular brands was our top scorer - receiving an impressive customer score of 83%. Whilst another is one of the worst-rated brands in our survey, getting a 59% customer score.
In fact, when we compared ownership of the five top scoring brands with ownership of all the other brands, we found that seven in 10 parents don't own a mattress from a top five brand.
This means it really pays to do your research.
By checking which brands are rated by parents and reading our expert reviews, you can find the perfect cot mattress for your little one.
Which? cot mattress testing is tough. It uncovers unsafe products and highlights the best of the best.
Our tests check:
We also put the cot mattresses through rigorous safety tests, making sure they don't have any choking hazards such as unsafe zips, and don't present a suffocation risk by being too soft.
Only cot mattresses that are safe, firm and durable are recommended.
Below are some of the most popular brands we've tested.
Number of mattresses we've tested: 2
Price range: £140 - £200
John Lewis was the sixth most-popular brand in our 2021 survey, with 7% of parents owning one of their cot mattresses.
However, we've also tested their pocket spring cot bed mattress - which has dozens of small springs, each wrapped in an individual cloth pocket. Pocket-sprung mattresses have a reputation for having better, more targeted body support. But does it provide the flat, firm surface needed to support your growing baby?
Number of mattresses we've tested: 4
Price range: £45 - £129
One in 10 parents from our 2021 survey own an Ikea cot mattress, making it the joint most-popular brand.
They have both foam core, and pocket sprung cot mattresses. In general, foam cot mattresses are cheaper but can lose their shape and dent more easily than sprung cot mattresses.
The Krummelur is their cheapest cot mattress we've tested, and it comes with a cover that's machine washable at 60°C - perfect for killing off germs and bacteria. But is it firm, and durable?
Number of mattresses we've tested: 4
Price range: £35 - £199
One in 10 parents we surveyed have a cot mattress from Mamas & Papas, making it the joint most-popular brand, along with Ikea.
We've tested foam, pocket sprung and even dual-core (pocket springs and fibre) models, but which Mamas & Papas cot bed mattresses performed well in our robust lab tests?
Number of mattresses we've tested: 1
Price range: Around £200
The Little Green Sheep is a less widely owned brand, with only 2% of parents we surveyed owning one of their cot mattresses.
However, we've highlighted them here as they have cot mattresses made from natural fibres, which are one of the firmest types of cot mattress. This may sound uncomfortable for an adult, but safety experts recommend an extremely firm and flat mattress as the best choice for your baby.
Little Green Sheep claim their natural twist mattress is free from harmful chemicals or toxins. But will it stay firm after years of use?