Cot vs Cot Bed: Which Should You Buy?

Both are fixed-sided beds that meet the same safety standard for cots, BS EN 716-1. The differences are size and what happens later.

• A cot is the smaller, simpler option: a frame around a 120 x 60 cm mattress, usually with two or three base heights. When your child outgrows it, it is done, and you move them to a toddler or single bed you buy separately.
• A cot bed is built around a bigger 140 x 70 cm mattress and is designed to be taken apart in stages: sides off and it becomes a low toddler bed, keeping the same mattress. Some models also remove the end panels to become a small sofa or day bed.

In the current UK market the cot bed has largely won. Of the 270 plus models in our fitment database, cot beds outnumber standard cots by more than three to one. That is worth knowing when you shop second-hand too: an unlabelled "cot" on Facebook Marketplace is more often a cot bed than not, which changes the mattress you need. If in doubt, look the model up.

The mattress gap sounds small on paper and is not in a nursery. A cot bed sleeps 140 x 70 cm against a cot's 120 x 60 cm, and the frame adds several centimetres to each figure once you include the posts and panels. Measure your intended wall against the external dimensions of the exact model before you decide; a cot bed that blocks a door swing or forces the changing table out of the room is not a bargain.

Two measuring tips from the fitment side of this site:

• Frame sizes vary more than mattress sizes. Two cot beds taking the same 140 x 70 cm mattress can differ by several centimetres externally depending on the design. Check the listed external dimensions of your exact model, not a generic figure.
• Do not buy the mattress by category. Most cot beds take 140 x 70 cm, but Boori cot beds take 132 x 70 cm and a SnuzKot takes 117 x 68 cm. Confirm your model's size before ordering; our cot mattress sizes guide covers every size in use.

Manufacturers quote cots as suitable from birth until roughly two years, and cot beds from birth to approximately four, with Silver Cross using exactly that wording across its range. Real children do not read the box, so treat those as ceilings, not promises. The practical limits are developmental:

• In the cot stage, the end comes when your child can climb out, which for many toddlers is somewhere between 18 months and two and a half years. Once they can clear the rail, the cot is a hazard rather than a container, whatever their age.
• In the toddler bed stage, a cot bed's 140 cm length keeps working until your child is roughly four, sometimes a little longer for smaller children. After that you are into a full single bed anyway.

So the honest comparison is: a cot covers roughly two years, a cot bed covers roughly four, and both end in a bed purchase eventually. The cot bed defers it by about two years and spares you the interim toddler bed.

A like-for-like cot bed usually costs somewhere between £50 and £150 more than the equivalent cot from the same brand, and its bigger mattress adds a little more. Against that, a separate toddler bed plus its mattress is rarely under £150 once you buy anything you would actually want. On pure arithmetic, the cot bed wins for a single child.

Where the maths flips:

• Siblings close together. If a second baby arrives while the first is still in the cot bed, you need a second cot anyway. Families planning a small age gap often do better with a standard cot, handed down, plus a cheap toddler bed for the eldest.
• Hand-me-down and resale plans. Cots and cot beds hold value well second-hand. A cot that serves two children sequentially can beat a cot bed that serves one, as long as each baby gets a mattress that passes The Lullaby Trust's second-hand checklist, or ideally a new one.
• Very small rooms. No saving is worth a room that does not function. The cot takes this one by default.

Yes to both. There is no safety requirement to start in a moses basket or crib; those exist for convenience and space, not because a cot is unsafe for a newborn. The NHS safer sleep rules apply identically whichever you choose:

• Always on their back, with their feet at the foot of the cot (the feet-to-foot position).
• On a firm, flat, waterproof mattress that fits with no gaps.
• Nothing else in the cot: no pillows, duvets, cot bumpers, soft toys, pods or nests.
• In your room for every sleep for at least the first six months.

That last point is the practical catch: a full-size cot bed is a lot of furniture to fit beside your own bed for six months. This is why many families run a bedside crib for the early months and have the cot or cot bed waiting in the nursery. If you go that route, see our guide on when to move your baby into the cot.

Buy the cot bed if the room fits it and your next baby, if any, is more than about two years away. It is the better long-term buy, and the toddler bed conversion genuinely gets used, unlike a lot of convertible nursery promises.

Buy the cot if space is tight, if you are planning a sibling within roughly two years, or if a good one is available cheaply second-hand from someone you trust. Spend the saving on the mattress, which matters more than the frame: firm, flat, waterproof, correct size, and new for each baby where possible.

Either way, confirm the mattress size from the exact model rather than the category. Pick your cot in the fitment search and we will show you precisely what fits it.