Choosing a cot Cot mattresses

Make sure the mattress you buy is the right size for your cot

You'll need to buy a cot mattress to go in your chosen cot or cot bed - and getting the right type and size is crucial.

The Foundation for the Study of Infant Deaths (FSID) recommends you buy a new cot mattress, or - if using a used mattress - carefully check that it's clean, dry and free from cracks or tears beforehand. Your cot mattress should be firm, with no sagging and fit the cot snugly, with no gaps.

Choosing a cot mattress

Here are our top tips to choosing a cot mattress:

Cot mattress size

Mattresses come in two basic sizes, to fit the equivalent sizes of cot generally available in the shops. Your cot will specify which type of cot mattress it requires: standard (56x118cm) or continental (60x120cm). If the mattress is the wrong size, your baby could be dangerously trapped in gaps between the cot and the mattress. As a rule, the gap between the mattress and the cot should be no more than 4cm (1.5 in).

If you buy a cot that is smaller or larger than the norm, you can get mattresses specially made to fit your cot.

Keeping the cot mattress clean

To keep the mattress as hygienic and clean as possible, choose one with a PVC-covering or a removable top panel that you can wash at a reasonably high temperature.

Try before you buy

Squeeze a selection of mattresses in the shop and choose one that feels firm rather than soft. To compare firmness, squeeze at the edges and at the centre. Your baby needs a mattress that provides good support and won't sag.

Look for a cot mattress that is 10cm thick. Anything thinner won't provide the support your baby needs. Thin foam in particular can lose its shape and dent easily. 

A travel cot mattress should no more than 10cm thick and 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 safety regulations that govern cot mattresses.

Safety first

Check it conforms to safety requirements: mattresses should carry the BSI number  BS 1877-10:1997.

Foam cot mattresses

Foam mattresses are good value for money and easy to clean

These traditional mattresses have a coiled spring interior with layers of felt and foam padding. They often have a cotton cover on one side and PVC or other wipe-clean material on the other.

Pros

• Many parents like the familiarity of a traditional spring mattress.
• The wipe-clean side is the recommended surface for your baby to sleep on because of the practical advantages, but you can flip it over onto the cotton side if you prefer – eg if it's hot and your baby feels clammy.

Cons

• More expensive than foam mattresses.
• The cotton side may be preferred for comfort but can be more difficult to keep clean (unless you buy a mattress with a removable panel).

Coir cot mattresses

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 to circulate through the mattress. These mattresses are available with a wipe-clean covering.

Pros

• One of the firmest types of mattress.
• Tend to be longer lasting because they hold their shape well, so could be a sensible purchase if you want to use it for more than one child.

Cons

• Less widely available than foam or spring interior.
• Can be more expensive than the alternatives.