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Cot Bed Mattress Buying Guide 

What is a cot bed mattress, and how do you choose the best one for your baby? We have the answers.

We tend to put a lot of careful consideration into buying a new mattress when we’re adults, but what about mattresses for babies? Cot bed mattresses are designed for the specific needs of very young children. 

Until they're about two years old, babies can spend up to half of their time in their cot. A comfortable mattress isn't just crucial for ensuring your baby has a restful sleep. It’s also essential to promote healthy growth and development in those vital early years.

Baby smiling laying in white cot.

What is a cot bed?

A cot bed is a bed specifically designed for a baby or young child. The cot sides are designed to prevent the child from falling or climbing out of bed. They are made with removable sides and an end panel that can transform the cot into a child’s bed when the child is a little older. 

What size is a cot bed?

The average size of a cot bed is around 140cm x 70cm. Cot beds come in various sizes, so if you have extra room, it is worth buying a larger cot bed initially as it will last longer. 

A cot bed is a budget-friendly way of providing your child with several years of comfort. They also become used to their own bed, giving them stability and reassurance at a time when continuity is vital for a growing child. Cot beds are often made of wood, so they can be painted to give them a touch of individuality.

What's the difference between a cot mattress and a cot bed mattress?

A cot bed mattress is slightly larger than a standard cot mattress (which measures 120cm x 60cm), making them ideal if you want to keep the same cot until your little one is ready to transition to a toddler mattress. For more information on the difference between cot and cot bed mattresses, read our Ultimate Guide to Kid's Bed Sizes.

What to consider when buying a cot bed mattress

There are a few different considerations you need to keep in mind when you’re buying a cot bed mattress for your baby, especially if you need to balance things like breathability for any allergies, or price if you don’t want to splash out on a mattress that they’ll outgrow!


Buying a cot bed mattress for your baby shouldn’t take a huge chunk out of your budget, however, buying new is recommended to ensure that the mattress is in good condition and it still firm enough for your wee one to support them correctly. You’ll find that cot bed mattresses range in price quite significantly, but the best options as recommended by parent and child awards and charities are around £100-£150. 


You should always use a firm and flat mattress for babies and young children. Soft or bulky bedding is not recommended for babies under 1 year old because of the risk of overheating and covering their head while they sleep. They should be supported along their whole body with a firm mattress. 


To create a safer sleeping environment for your baby and ensure they can breathe freely, it is always worth checking that your cot bed mattress is allergen-free. For example, Silentnight cot bed mattresses are hypoallergenic, helping to reduce the chance of dust and bacteria disturbing your baby's sleep.


Having a waterproof cover or protector will be a life saver for you in your child’s early years! You’ll definitely appreciate how much easier a waterproof cover makes your life when nighttime accidents inevitably happen. 

Read our guide to The Best Cot Mattresses For 2024 to discover our Product Experts' top recommended baby mattresses.

Baby sleeping in a cot bed.

Should you get a foam cot bed mattress?

Foam cot mattresses are a good choice for babies and young children. They offer plenty of support but with no compromise on comfort. Babies are often too light to feel the benefit of targeted pressure relief from pocket sprung mattresses, whereas foam is able to mould to their shape whatever their weight and keep them supported at every point of contact.

How do you clean a cot bed mattress?

Most cot bed mattresses come with a waterproof liner and a washable cover. These covers can be quickly and easily removed and popped into the washing machine on a 60° cycle. Waterproof covers can be wiped clean quickly and easily in the event of a night-time accident. Plud, a disinfectant spray can be used on waterproof covers.

If a stain has soaked through to the foam layer, it can be spot-treated with vinegar and baking soda - read our guide on cleaning a foam mattress, but make sure whatever products you use are safe for your baby.

For more help, read our complete guide to buying your child a kids' mattress, which includes tips on when to upgrade to a bigger mattress, as well as how often you should replace it.