While you, as a parent, may want a soft mattress for extra comfort, a cot mattress should be flat and firm to provide a safe and supportive night's sleep for your little one.
But with prices ranging anywhere from £50 all the way up to £200, it can be hard to know if splashing out is worth it.
We've tested more than 35 cot mattresses at Which?, rigorously assessing each one's support, durability and safety so that we only recommend the best.
On average, a Best Buy cot mattress costs £89, while a Don't Buy would typically set you back £121.
With price not being an indicator of quality, read on to discover our buying tips that will actually get you a great cot mattress.
We took all our available reviews as of January 2022, and compared their retail price to the overall test score.
You can see in the graphic that there is no correlation between the price of a cot mattresses and how well it performs.
So using price as an indicator of quality may not mean you get you the best cot mattress.
Typically, the more expensive cot mattresses have fancy features and claims, but a cot mattress simply needs to provide a supportive night's sleep, be safe for your baby or child, and be easy to clean.
If it excels at these three things we will recommend it.
The average price of a Best Buy cot mattress is £89; the average price of Don't Buys is £121.
So you don't need to be paying triple figures to get a cot mattress with excellent performance.
Our rigorous tests replicate years of use, so we can tell you if a cot mattress that looks great brand new will still be doing so years down the line - something other reviews can't. We also test to the current cot mattress safety standard, so we reveal any mattress that could be a danger.
Press your hand firmly into the centre of the mattress. There should be resistance and it should bounce back immediately after you remove your hand. Repeat this at the edges of the cot mattress. Again, there should be resistance and it should bounce back immediately.
Check it can be machine-washed (not all can) and that you can wash it at temperatures up to 60°C. This ensures that all nasty germs get killed in the wash, keeping your child's bed hygienic.
The Lullaby Trust suggests a waterproof mattress is more important than a breathable one. This is because having a waterproof cover on your baby's cot mattress helps to stop bacteria building up inside the mattress, reducing the risk of illness. A baby's temperature can be regulated through other means.
Manufacturers want their product to stand out from the crowd, but The Lullaby Trust says it's best to ignore claims such as 'eliminates allergens', 'Reduces risk of SIDS' and 'Reduces the risk of flat-head syndrome'. For even more advice on recommended products for safer sleeping, see .