Which mattress and bedding should you choose for a carrycot or cradle?

Why must the mattress fit the carrycot or cradle exactly?

A perfectly fitting mattress protects your baby better than a poorly fitting premium model: a gap between the mattress edges and the sides creates a risk of your baby becoming trapped or even suffocating if they turn into it while asleep.

Dimensions vary between models: a carrycot usually takes an oval mattress, while a cradle may take a rectangular or oval one. Always check the measurements in the sleeping space’s instructions rather than assuming there is a universal size. This precision matters more than any other criterion: density or thickness can never compensate for a poorly fitting mattress.

Thickness, density and firmness: guidelines for a safe baby mattress

Mattress firmness is a matter of safety, not perceived comfort. While adults may instinctively seek softness, a baby needs a firm sleeping surface that yields only slightly under their low weight, without dipping beneath their head. A mattress that envelops the baby too much increases the risk of suffocation, while excessive firmness may contribute to a flattened head: the right balance lies between these two extremes.

Useful guidelines:

• a density generally between 20 and 30 kg/m³, depending on the material: foam, coconut fibre or latex;
• a thickness of between 5 and 10 cm, as a thicker mattress is unnecessary given a newborn’s low weight;
• a simple test: press your hand flat against the mattress. It should spring back almost immediately, without leaving a lasting indentation.

This guideline applies to both carrycots and cradles before the move to a cot. At Charlie Crane, the foam and natural-fibre mattresses designed for KUMI, KUKO or KODO follow this approach to providing appropriate support.

Natural or synthetic materials: what really matters in a mattress’s composition

A mattress has two main components: the core (foam, natural latex or coconut fibre) and the cover (cotton, bamboo or wool). For comfort and ease of care, the choice is largely a matter of personal preference: an organic cotton or bamboo cover feels pleasant and is breathable, making it ideal as temperatures change. Oeko-Tex-certified foam offers good value for money without unnecessary chemical treatments; coconut fibre and natural latex appeal for their breathability and hypoallergenic properties.

But mattress safety depends above all on density and firmness, not the material. A mattress that is too soft poses a risk of suffocation and may contribute to flat head syndrome, whatever it is made from. This is the criterion assessed under the NF EN 16890 standard to ensure support suited to a newborn’s low weight. A firm, correctly sized foam mattress can therefore be just as safe as a latex or coconut fibre model. Natural materials remain valuable for their softness against the skin and lack of biocidal treatments, but they never replace checking the density, thickness and exact fit to the sleeping space.

Which bedding is suitable for a carrycot or cradle?

Bedding works as a system, with each element protecting and complementing the mattress:

• The fitted sheet: it must fit the mattress exactly to avoid uncomfortable creases or potentially dangerous gaps. Choose a soft, breathable natural material such as organic cotton.
• The mattress protector: waterproof but breathable, it protects against small leaks and spit-up while allowing air to circulate. A protector that prevents the foam from breathing encourages dampness and unpleasant odours.
• The baby sleeping bag: choose one for the season and your child’s age, so they are neither too hot nor too cold. It replaces loose sheets and blankets, which are less safe in a carrycot or cradle.

Designed as a coordinated set, the bedding becomes a discreet companion to peaceful sleep. If you're looking for a baby cradle, check when buying that its dimensions are compatible with the available bedding.

How long can you use a carrycot or cradle mattress, and how can you prepare for the transition?

Babies generally move out of a carrycot between 4 and 6 months, as soon as they begin to roll over unaided or push up on their arms. A cradle offers a little more time, often until 5 or 6 months, before the move to a cot. This short period of use is why the mattress should never be considered adaptable as your child grows: its dimensions remain fixed and do not adjust to the child’s growth.

To prepare for this transition without stress:

• Watch for physical signs: your baby touches the sides, pushes themselves up or seems cramped.
• Get the cot ready in advance to avoid a rushed change.
• Choose a new mattress that fits the next cot exactly, with a thickness and density suited to a more mobile child.
• Keep the same cosy feel in the bedding to help your baby feel reassured in their new room.

At Charlie Crane, the KUKO carrycot is designed for little ones from birth to around 5–6 months, while the KUMI cradle can be used up to 6 months. This continuity helps you prepare for each stage without having to make several purchases in a rush, while retaining natural materials and European manufacturing.

Frequently asked questions

Is it essential to avoid any gap between the mattress and the carrycot? Yes: a gap between the mattress and the sides creates a risk of your baby becoming trapped or even suffocating. The mattress dimensions must match the sleeping space exactly, without exception.

Does a firm mattress make a baby less comfortable? No. A newborn’s comfort depends on support suited to their low weight, not softness. A mattress that is too soft can, on the contrary, pose a safety risk.

Does a mattress made from natural materials guarantee safety on its own? No. Natural materials offer softness and an absence of chemical treatments, but real safety depends on density, thickness and an exact fit to the sleeping space.

Can you reuse the same mattress in a cot? No, because the dimensions of a mattress for a carrycot or cradle are fixed and will not fit a larger cot. You need a new mattress that fits the next cot exactly.

How do you choose the right baby sleeping bag? Choose it according to the season and your child’s age to avoid them being too hot or too cold, alongside a well-fitting fitted sheet and mattress protector.