When to Move Baby from Cot to Toddler Bed

Most toddlers do not need to leave their cot until they start climbing out or the top rail drops below their chest. That usually happens somewhere between 18 months and 3 years, and the NHS says there is no rush to move them before then. If your child sleeps safely and happily in their cot, you can leave them there.

The real question is not "how old should my toddler be?" but "is there a safety reason to move now?" The answer comes down to a few clear signals, and this guide covers each one, explains how to make the switch smoothly, and recommends the products that actually help.

Signs Your Toddler Is Ready to Move

They can climb out of the cot. This is the single biggest safety trigger. A toddler who can get one leg over the top rail is at risk of falling, especially if they try to climb out in the dark. If you see them attempting it even once, start planning the move. Some parents add a safety gate to the bedroom door as a temporary measure while you set up the new bed.

The top rail is at chest level or below. Standards for cots require the minimum mattress height to leave at least 60cm between the top of the mattress and the top rail (BS EN 716 in the UK). When your toddler stands and the rail drops to their chest, the cot has done its job. Your child's paediatrician or health visitor can confirm this at a routine check.

They ask for a bed. Some toddlers become aware that older siblings or friends sleep in beds and want to copy them. If they are expressing interest and they are over 18 months, that is a reasonable time to try. The transition is usually easier when they feel involved in the decision.

You are expecting another baby. If you need the cot for a new arrival, move your toddler to their new bed at least six weeks before your due date. That gives them time to adjust before the disruption of a new sibling. Rushing both changes at once almost always makes bedtime harder.

Why There Is No Fixed Age

You will hear parents say "we moved at two" or "we waited until three" as though there is a right answer. There is not. The Lullaby Trust focuses on sleep safety, not age milestones. A cot with properly fitted sides and the right mattress is the safest sleep environment for a child who fits in it comfortably.

Child sleep specialists often encourage families to wait until closer to age 3, when a toddler's understanding of rules is greater and they are less likely to get out of bed repeatedly at night. Earlier moves can work, but they tend to come with more bedtime disruptions in the first few weeks.

The bottom line: if your toddler is safe in the cot and sleeping well, there is no medical or developmental reason to move them. You are not holding them back by keeping them in the cot.

How to Make the Switch

Option 1: Convert the cot bed. Many UK cot beds are designed to convert into toddler beds by removing one side rail and lowering the mattress to the lowest setting. Check your cot bed's manual or brand website for conversion guides. This is usually the cheapest option since you already own the frame and mattress. If you are still shopping for a cot bed, look for one with a clear conversion path - our best cot beds guide compares the top options on the UK market.

Option 2: Put the mattress on the floor. Take the cot mattress out and lay it directly on the floor. It removes the fall risk entirely while you decide on a proper bed. Make sure the mattress is firm, clean, and fitted with a tight sheet. This works well as a short-term step, especially if your toddler is under 2. A Maxi-Cosi travel cot mattress also works as a temporary floor option if you have one spare.

Option 3: Buy a toddler bed. A toddler bed uses a smaller mattress (usually 140cm x 70cm) and often comes with built-in side rails. They are sized for children up to about 5 years old and sit low to the ground. If you are choosing this route, look for one that converts further into a single bed for longer use.

Whichever option you pick, keep the room as familiar as possible. Same bedding, same nightlight, same routine. The less that changes at once, the smoother the transition tends to be.

Safety Steps After the Move

Once the cot is gone or converted, a few adjustments keep your toddler safe in their new setup:

Install a bed guard. A removable guard rail on the open side of the bed prevents falls during the first few weeks. Some toddler beds have built-in rails. For a standard single bed, a clamp-on guard rail is a cheap, practical addition. A basic safety gate across the bedroom door also works well if your toddler is getting up at night and wandering.

Check the room again. Your toddler can now get out of bed and walk around. Revisit the baby-proofing guide for your home and make sure the bedroom door has a child-safe handle, sockets are covered, and any heavy furniture is anchored to the wall.

Keep a consistent routine. The bedtime routine matters more during a transition, not less. Stick to the same steps: bath, pyjamas, story, bed. If they get up, walk them back calmly and quietly. Most toddlers settle into the new bed within one to two weeks.

Common Mistakes to Avoid

Moving too early because of peer pressure. Other parents may move their toddler at 18 months, but that does not mean your child needs to. If your toddler is not climbing out and the cot still fits, waiting is perfectly fine.

Moving during a disruptive period. A new nursery, a holiday, illness, or starting nursery are all bad times to add another change. Pick a quiet stretch where the household routine is stable.

Skipping the bed guard. Even if your toddler sleeps soundly, they will roll around more in an open bed. A guard rail costs under £20 and prevents the most common fall injury.

Going straight to a high single bed. If your child is under 2, a toddler bed or a floor mattress is safer than a standard single bed raised on a frame. The lower the sleep surface, the lower the fall risk. A low-profile cot bed that converts to a toddler bed keeps things safe without buying a whole new piece of furniture.

What About Cot Bed Mattress Size?

Most UK cot beds use a mattress that is 140cm x 70cm. When you convert the cot to a toddler bed, the same mattress stays in place. If you are buying a new toddler bed, check that it fits a 140cm x 70cm mattress before purchasing. Some brands use slightly different dimensions, so measure before you buy.

A good cot bed mattress should be firm (not soft), at least 10cm thick, and fit snugly with no gaps at the edges. If the mattress is worn, sagging, or more than five years old, replace it at the same time as the transition. A well-fitted travel cot mattress can also work as a temporary floor mattress while you decide on a permanent solution.

What If They Keep Getting Out of Bed?

This is normal, especially in the first two weeks. Toddlers are exploring a new level of independence and testing boundaries. The approach that works for most families is consistent and boring: walk them back to bed, tuck them in, say goodnight, leave. No lengthy negotiations, no extra stories, no angry reactions. Most children stop getting out of bed repeatedly within a week or two when the response is predictable.

If it continues beyond a few weeks, check that the room is not too hot or cold, that the bed is comfortable, and that the white noise machine or nightlight is still running. Sometimes the disruption is about the environment, not the bed itself. A consistent white noise machine can help signal that it is sleep time, especially if your toddler now gets out of bed to find you.

The cot-to-bed transition is one of those parenting milestones that feels bigger than it is. Most toddlers adjust within a week or two, and the right setup makes the difference. Whether you convert the cot, floor the mattress, or buy a new toddler bed, pick the option that fits your child's readiness and your budget. A Momcozy white noise machine and a consistent routine will carry you through the adjustment period.

For more sleep guides, visit My Baby Now.