Buying a mattress for your baby’s cot bed might seem like a simple task, but getting the measurements right is more important than you might think.
A mattress that’s too small can leave gaps around the edges, while one that’s too large may not sit flat inside the frame. Even a small difference in measurements can affect how securely the mattress fits.
One of the most common sizes you’ll come across when shopping for a UK cot bed is a 140 x 70cm mattress. You may also see it listed as 70 x 140cm, 70×140 cot mattress or 140 x 70 cot bed mattress. Although the measurements are written differently, they refer to the same standard size.
But what type of cot bed takes a 140 x 70 mattress? Is it suitable for toddlers? And can you use a 160 x 70 or 132 x 70 mattress instead?
In this guide, we’ll explain everything you need to know about 140×70 cot mattresses, including dimensions, compatibility, mattress thickness and how to choose the right one for your child’s bed.
A 140 x 70cm cot mattress is a mattress measuring:
It is commonly used in standard UK cot beds, which are larger than traditional cots and are designed to convert into toddler beds as your child grows. See our guide to the suitable age to use a cot bed.
The larger sleeping area means your child can continue using the same mattress when the cot bed is converted, provided the mattress remains in good condition and is suitable for the converted bed.
You may see this mattress size described in several ways when shopping online:
These terms generally refer to the same dimensions, with the length and width simply listed in a different order.
If you’re looking for a mattress in this size, explore Babymore’s 140 x 70cm cot bed mattresses.
Yes. A 140 x 70cm mattress is a common standard size for UK cot beds.
However, it is important to understand the difference between a cot and a cot bed because they do not necessarily use the same mattress dimensions.
Here’s a quick comparison:
| Bed type | Typical mattress size | Description |
|---|---|---|
| Standard cot | 120 x 60cm | Smaller sleeping space for babies |
| Standard cot bed | 140 x 70cm | Larger sleeping space that converts into a toddler bed |
| Compact cot bed | May use 120 x 60cm | Smaller design with different mattress requirements |
| Mini cot | Often around 100 x 50cm | Compact option for smaller spaces |
| Crib or Moses basket | Varies by model | Requires a mattress made for that specific product |
Not every cot bed uses a 140 x 70cm mattress. Some compact models are designed for smaller dimensions, so always check the product specifications before ordering. For smaller options, see our 120 x 60cm cot mattress size guide, and for cribs and Moses baskets see Moses basket vs crib.
For more information about standard mattress dimensions, read Babymore’s Cot Mattress Size Guide.
There is no difference in the actual dimensions.
A 140 x 70cm mattress measures 140cm in length and 70cm in width. A 70 x 140cm mattress simply lists the width first and the length second.
Both descriptions refer to the same mattress size.
This is worth remembering when shopping online because different retailers may list their products using different measurement formats.
For example:
If you see a mattress advertised as 70x140cm, you don’t need to look for another product listed as 140x70cm. The dimensions are identical.
However, always check the mattress depth as well as its length and width.
A 140 x 70cm mattress is generally designed for a cot bed with internal dimensions suitable for that mattress size.
If you’re searching for what size baby cot to buy for a 140×70 mattress on Amazon or another retailer, look specifically for cot beds that state they are compatible with a 140 x 70cm mattress.
Don’t rely on the external dimensions of the furniture or the product title alone.
The most important measurement is the internal sleeping area.
Before buying a cot bed (our cot bed buying checklist can help), check:
A cot bed may look large enough from the outside but still have a different internal sleeping area.
Babymore offers several cot bed designs, so you can compare options in its cot and cot bed collection.
Yes, a 140 x 70cm cot bed mattress is generally designed to remain in use when a compatible cot bed converts into a toddler bed.
This is one of the main advantages of buying a cot bed rather than a traditional cot.
A cot bed usually starts with raised sides to create an enclosed sleeping space for a baby. As your child grows, some components can be removed or rearranged to create a toddler bed.
The mattress can remain the same, which means you won’t necessarily need to buy a new one during the transition. Our guide to moving from cot to toddler bed covers the next steps.
However, there are a few things to remember:
If you’re considering a convertible design, Babymore’s Safe Use of Cot Bed Guide explains when and how to make the transition.
No. A 160 x 70cm mattress is 20cm longer than a 140 x 70cm mattress, although both have the same width.
This difference means they are not interchangeable.
A 160 x 70cm mattress is not a standard UK cot bed mattress size. It may be intended for a specialist bed frame or a non-standard furniture design.
If your cot bed requires a 140 x 70cm mattress, a 160 x 70cm option will be too long and will not fit correctly.
Never try to force a larger mattress into a smaller cot bed or fold, bend or compress it to make it fit.
Always use the exact mattress dimensions recommended by the furniture manufacturer.
A 132 x 70cm mattress is another non-standard size that you may come across when searching for replacement cot mattresses.
It is 8cm shorter than a standard 140 x 70cm mattress, even though the width remains the same.
This difference may seem small, but it can leave a noticeable gap between the mattress and the cot frame.
For example, if your cot bed requires a 140 x 70cm mattress, using a 132 x 70cm mattress could leave an 8cm difference in length.
This is not a suitable replacement.
If your existing cot bed requires a 132 x 70cm mattress, check the manufacturer’s instructions and contact the manufacturer to confirm the correct replacement dimensions.
Do not assume that a standard 140 x 70cm mattress will be suitable simply because the difference is relatively small.
A properly fitted mattress is essential for reducing the risk of your baby becoming trapped between the mattress and the cot frame.
A typical 140 x 70cm cot bed mattress is around 10cm thick.
However, the correct thickness depends on the cot bed manufacturer’s specifications.
A mattress that is too thick can reduce the effective height of the cot sides, while one that is too thin may not provide the intended sleeping surface. Our guide to the importance of a cot mattress explains why this matters.
When choosing a mattress, check:
Babymore’s 140 x 70cm cot bed mattresses are generally 10cm deep, with different internal constructions available.
You can compare the Babymore Cot Bed Mattress Collection to explore the available options.
For more information about mattress depth and support, read the Babymore Mattress Guide and how thick a baby mattress should be
Getting the right dimensions is only part of choosing a suitable mattress. It also needs to fit securely inside the cot bed.
A mattress that leaves large gaps around its edges can create an entrapment hazard, particularly for younger babies.
Here are a few checks to make before using a new mattress.
Measure the inside of your cot bed rather than the external frame.
You should check the length and width of the sleeping area, making sure they match the mattress specifications.
The mattress should fit snugly against the sides of the cot bed.
The Lullaby Trust advises that the gap between a cot mattress and the cot sides should be no more than 3cm. See our guide to the best mattresses and bedding for babies.
Once positioned inside the cot bed, the mattress should lie completely flat.
It should not bend, curl upwards or become compressed along the edges.
A suitable mattress should be firm, flat and free from damage.
Look for:
For more practical guidance, read Babymore’s Cot Safety Guide.
Once you’ve confirmed that your cot bed requires a 140 x 70cm mattress, the next step is choosing the type of mattress that suits your preferences.
Different mattress constructions offer different features, but the most important requirements remain the same: a firm, flat and properly fitted sleeping surface. Our guides to the types of baby mattress and what baby mattresses are made of explain the differences.
Babymore offers several options in the 140 x 70cm size.
The Babymore Eco Fibre Cot Mattress features a superior fibre core designed to provide support and resist denting.
Key features include:
It is a practical option for parents looking for a fibre mattress with easy-care features. Read more about breathable baby mattresses before you decide.
The Babymore Pocket Sprung Cot Bed Mattress features individually pocketed springs designed to provide responsive support. Our guide to pocket sprung cot mattresses explains how they work.
It also includes:
The Babymore Premium Core Cot Bed Mattress features a two-sided design, with one side intended for infants and the other for toddlers.
Its key features include:
Always follow the product instructions when turning or using a dual-sided mattress.
The best choice depends on the features you value most.
| Mattress type | Main feature |
|---|---|
| Eco Fibre | Supportive fibre core and easy-care cover |
| Pocket Sprung | Individually pocketed springs |
| Premium Core | Dual-sided infant and toddler design |
You can also browse the complete Babymore baby mattress collection to compare available sizes and constructions.
Choosing the right 140 x 70 cot mattress is about more than finding the correct measurements. You also need to consider its thickness, firmness, construction and how securely it fits inside your child’s cot bed.
While 140 x 70cm is a common UK cot bed mattress size, not every cot bed uses the same dimensions. Measurements such as 132 x 70cm and 160 x 70cm are not direct alternatives, so always check your furniture manufacturer’s instructions before ordering.
If you’re looking for a replacement or setting up a new nursery, explore Babymore’s cot bed mattress collection to find a suitable option for your child’s sleeping space.
