You’ll often see “120 x 60 cm” quoted as the standard cot mattress size in the UK. But “standard” doesn’t always mean it fits yours. Some cot beds take a bigger mattress, some cribs take a much smaller one, and a mattress that’s just a few centimetres out can leave dangerous gaps. So what does 120 x 60 cm actually mean, is 60 x 120 the same thing, which cots take this size, and how do you check the fit? This guide answers all of that.
A 120 x 60 cm cot mattress is 120 cm long and 60 cm wide (about 47 x 24 inches), and it is usually around 10 cm thick. It is the standard mattress size for UK cots and for some smaller cot beds. “60 x 120” means exactly the same size. It will not fit a larger 140 x 70 cm cot bed, a Moses basket or a crib. It should fit the frame snugly, with no more than a 3 cm gap at any edge.
Cot mattress sizes are written as length x width, then thickness. So a 120 x 60 x 10 cm mattress is 120 cm long, 60 cm wide and 10 cm thick.
Looking for the full picture across all baby bed sizes? See our guide to cot and cot bed mattress sizes.
| Bed type | Take a 120 x 60 cm mattress? |
|---|---|
| Standard UK cot | Yes. This is the standard size. |
| Smaller cot bed | Often yes. For example, Babymore’s Iris Cot Bed takes a 120 x 60 cm mattress (not included). |
| Larger cot bed | No. Most take a 140 x 70 cm mattress. |
| Small or mini cot | Sometimes. Some take a smaller 100 x 50 cm mattress, so check. |
| Crib or Moses basket | No. These use their own, smaller sizes. Our Moses basket vs crib guide explains the differences. |
| Travel cot | No. It has its own mattress. See travel cots vs standard cots. |
| Cots from outside the UK | Not always. Sizes can differ. |
The golden rule: check the mattress size in your cot’s instructions or on its product page, or measure the inside of the frame. Don’t assume. If you’re unsure whether you have a cot or cot bed, read our guide to the difference between a cot and a cot bed or the guide to choosing the right cot bed. Buying a new one? Our cot bed buying checklist covers what to check.
No, in both directions.
A mattress should fit snugly. Babymore’s guidance is no more than a 3 cm gap between the mattress and the sides of the cot. To check, push the mattress into one corner and measure the gap on the opposite side. If it’s more than 3 cm, choose a different size. For more on safe set-up, see our cot safety guide and cot bed safety guidelines.
About 10 cm. Babymore’s mattress guide explains that around 10 cm gives support and keeps its shape, that 7 to 8 cm mattresses are better for occasional use, and that no mattress should be thicker than 10 cm. Also look for BS EN 16890:2017, the standard for cot mattresses. Want to know why the mattress matters so much? Read why a good cot mattress is important.
Babymore makes four mattress ranges in this size. All of these are 120 x 60 x 10 cm, meet BS EN 16890:2017, BS 1877 Part 10 and BS 7177, and have a removable BabyTec cover that can be washed at 60°C (see how to clean a baby mattress).
| Mattress | Core | Good to know |
|---|---|---|
| Premium Core Cot Mattress | Pocket sprung core with 258 micro pocket springs, natural coir layer and fibre lining | Two-sided: one side for infants and one for toddlers (see when to flip a dual-sided mattress) |
| Pocket Sprung Cot Mattress | Individually pocketed springs | See our pocket sprung mattress guide |
| Deluxe Sprung Cot Mattress | Traditional Bonnell spring unit in dent-resistant nursery fibre | British made |
| Eco Fibre Cot Mattress | Dent-resistant fibre pad | A simple, fibre-only option |
Not sure what the differences between these types are? Our mattress guide compares them, and our guide to types of baby mattress goes into more detail. You can also read what baby mattresses are made of and how breathable baby mattresses work.
Often, yes. Toddler beds are usually cot-sized, so a 120 x 60 cm mattress and bedding can usually be reused when your child moves on. Check the size of your toddler bed first. Our guide to moving from a cot to a toddler bed explains when to make the move, and when it’s time to change from a cot to a bed covers the signs to look for.
If your cot is a standard UK cot, 120 x 60 cm is almost certainly its mattress size. If it’s a cot bed, check first, because many take the larger 140 x 70 cm. Measure, check the gap, and look for a mattress that meets the safety standards.
For the wider picture, see our guide to cot and cot bed mattress sizes and our mattress guide. Setting up the rest of the nursery? Our nursery checklist is a good next step.
