A convertible cot (often sold as a cot bed) is a cot whose sides come off, or whose base converts, so that it becomes a child's bed that can be used until the age of five or six. It is worth it when it genuinely replaces two purchases, first the cot and then the first proper bed, with no compromise on safety during the first phase. It is far less useful when the second phase is never used, or when its design makes it harder to settle a newborn safely.
This guide explains what ‘convertible’ actually covers and which safety criteria really matter. It also sets out the signs that it is time to take the sides off, and the situations where a simple cot is still the best choice.
What exactly is a convertible cot?
The term covers several designs that do not all last the same length of time in practice.
- The cot that converts into a toddler bed: the most common model. One or both sides come off, the base is lowered, and the bed keeps the size of the original mattress, most often 70 × 140 cm. This is the only design that truly deserves to be called convertible for a baby.
- The 60 × 120 cm cot with a conversion kit: it becomes a small, low bed that is too short for a four-year-old. The second phase does not last long.
- The ‘3-in-1’ or ‘4-in-1’ bed: crib, cot, toddler bed and then a bench or desk. Each stage adds parts, screws and adjustments, and the last one is rarely used.
- The convertible bedside crib: a crib that attaches to your bed and later becomes a small stand-alone bed. It serves a different purpose, covered in our guide to choosing a bedside crib and knowing how long it lasts.
So before comparing models, ask yourself one simple question: what bed do you want your child to have at three? If the answer is a 90 × 190 cm bed, a convertible cot will only save you an in-between step.
Convertible cot: which safety criteria should you check?
The safety rules are the same as for any other cot. In Europe, children's cots for domestic use fall under the EN 716 standard. We do not go into its figures here, as they are not freely available. The figures below come from Health Canada, whose regulations are public and whose orders of magnitude are comparable.
The spacing between the bars
Health Canada requires that ‘the bars are no more than 6 centimetres apart’. Any wider and a baby's head could get trapped. On a convertible cot, also check the gap between the last bar and the corner post, and the gap between the bars and the end panel when a side has been removed.
The mattress and how well it fits
The same source sets two limits: ‘the space between the sides of the cot and the mattress must not exceed 3 centimetres’, and a cot mattress must be no more than ‘15 centimetres thick’. A mattress that is too thick reduces the effective height of the bars. Our guide to choosing a firm, well-fitting baby mattress covers the sizes and firmness to look for.
The adjustable base
A convertible cot almost always has a base with two or three height positions. The high position makes the first few months easier. As soon as your baby ‘is able to sit up or get on all fours’, Health Canada recommends ‘lowering the mattress to the lowest level’. At the same time, you should ‘remove mobiles and other hanging toys’. This step often comes between six and nine months: our guide to the age when babies start to stand will help you plan ahead.
Drop sides and old cots
Cots with a sliding side that lowers so you can lift your child out have been taken off the Canadian market: ‘since 29 December 2016, it has been illegal to sell, import, manufacture or advertise’ these cots. The reason lies in failures of the mechanism, which create a gap between the side and the mattress. A second-hand convertible cot handed down in the family therefore deserves a careful inspection: Health Canada rules out cots ‘made before September 1986’ and, for a cot more than ten years old, asks you to check ‘that there are no missing parts’.
What should not be in the cot
A convertible cot changes nothing here: no pillow, no blanket, no cot bumper and no sleep positioner during the first year. A sleeping bag suited to the season replaces the duvet, and a well-fitted sheet is all you need. The French safe sleep recommendations are summarised in our article on safe sleep for babies.
Convertible cot: until what age should the sides stay on?
There is no official age for moving to a bed without sides. Public guidance is based on two signs, not on a birthday. Health Canada advises moving to a toddler bed ‘when your child can climb out or is taller than 90 centimetres, whichever comes first’. The Institut national de santé publique du Québec (Quebec's public health institute) uses the same thresholds: the cot is used ‘until the child is 90 cm tall’ or ‘until they are able to climb out of the cot’.
In practice, this usually means somewhere between eighteen months and three years. A paediatric hospital in the United States notes that most children ‘move to a bed at around two years old’. The decisive sign is a leg thrown over the rail when the base is already at its lowest. A child who climbs is no longer safe behind bars: a fall from the top of the side is more dangerous than climbing freely out of a low bed.
This is exactly where a convertible cot comes into its own. Removing a side on the day the climbing starts saves you a rushed purchase, and your child keeps their mattress, their sheet and everything that looks familiar.
How does the move to a big bed go?
The tips below are based on common practice and on recommendations from paediatric services, not on a standard.
- Choose your moment: not the same week as starting nursery, a new baby or a house move. A calm period makes it easier to adjust.
- Keep the bedtime routine: same time, same steps, screens off. A steady routine matters more than the bed itself.
- Plan for a removable bed guard: paediatric services recommend a bed rail with ‘no gap’ between it and the mattress, to limit falls in the first few weeks.
- Wait until two for a pillow, and then choose a small, firm one.
- Do not place the bed under a window, fix furniture to the wall and fit a safety gate at the top and bottom of the stairs: a child who gets out of bed alone will wander at night. Our guide to babyproofing your home lists the points to review.
- Calmly walk your child back to bed when they get up, as many times as needed on the first few evenings, without discussion.
Convertible cot, simple cot or floor bed: which should you choose?
There are three different approaches, and none is better in absolute terms.
The simple 60 × 120 cm cot
The cheapest, the most compact and easy to resell. It lasts about two and a half years, after which your child moves straight to a 90 × 190 cm bed. In a small home, this is often the most sensible choice.
The 70 × 140 cm convertible cot
It costs more to buy and takes up more space from day one, but it covers five to six years with the same mattress. It pays off if you are sure you will stay in the same home and if the second phase will really be used. A child who is tall for their age outgrows it at around five.
The floor bed
A mattress placed on the floor, with no sides, is the preferred option in some Montessori-inspired bedrooms. It removes the climbing issue altogether, but shifts your attention to the whole room, which must be fully childproofed. For the first year, the sleep recommendations remain the same whatever the surface: firm, clear and on the back. A thick, foldable play mat placed at the foot of the bed cushions those first climbs out and doubles as a play area on waking.
The most common mistakes with a convertible cot
- Buying a ‘convertible’ 60 × 120 cm model thinking it will last until age six: the mattress is simply not long enough.
- Removing a side too early, before eighteen months, because the instructions allow it. The sign that matters is climbing or height, not what is technically possible.
- Keeping a mattress that is too thick or too soft because it ‘will last until six’. Firmness is judged for the baby, not for the five-year-old.
- Forgetting to lower the base as soon as your baby can sit up.
- Losing the conversion parts. Keep the screws, kit and instructions in a pouch attached under the base.
- Assembling a second-hand cot without instructions or without all its parts. If in doubt, a question to the manufacturer costs less than a makeshift repair.
Key takeaways
A convertible cot is a good buy if it is the 70 × 140 cm size and you plan to use it for five years in the same home. Its safety criteria are those of a standard cot: closely spaced bars, a well-fitting mattress no more than 15 cm thick, an adjustable base and no sliding side. The move to a bed without sides depends on two signs, climbing or a height of 90 cm, not on age. If you are planning a big bed from age three, a simple second-hand cot does the same job for much less.
Sources
- Santé Canada, ‘Lits d'enfant, berceaux et moïses’, page published on 20 November 2024, updated on 3 November 2025.
- Institut national de santé publique du Québec, Mieux vivre avec notre enfant, ‘Aménager un environnement sécuritaire pour votre enfant’, updated on 17 February 2026.
- Monroe Carell Jr. Children's Hospital at Vanderbilt, ‘Moving Your Toddler From Crib to Bed’, medically reviewed on 1 September 2025.
- Agence de la santé publique du Canada, ‘Conseils pour un sommeil sécuritaire des nourrissons à l'intention des grands-parents’, page updated on 29 January 2026.
