Moving from a cot bed to a big bed is a proper milestone, and the mattress is one part of it you can get exactly right before the day comes. Here's what we'd tell a friend.
When to make the move
There's no fixed age. Many children move on from a cot bed somewhere between 18 months and 3 years, often because they've started climbing out, they've outgrown it, or a new baby needs it. If your child is sleeping well and safely where they are, there's no rush.
Which size will the new bed take?
That depends on the bed rather than the child's age. The usual options are:
- A toddler bed. Most take the same 140 x 70 cm mattress as a cot bed, so your current mattress may move across if it's in good condition.
- A single bed. At 90 x 190 cm (3ft x 6ft3), it's the most common size for children and usually lasts into the teenage years. See our kids single mattresses.
- A small single or a shorty. At 75 x 190 cm and 75 x 175 cm, they're handy in smaller rooms and on some cabin beds and bunks. See small single and shorty mattresses.
- A floor bed. Popular in Montessori-style rooms, and often a cot bed or single size. See floor bed mattresses.
Whichever bed you choose, measure the inside of the frame before you order. Our guide to measuring your bed shows how.
How firm should it be?
Toddlers need a firm, flat mattress. Once children are past the toddler stage, most sleep well on medium to medium-firm, which is 5 to 8 on our 1 to 10 firmness scale. Very firm mattresses tend to feel hard to a light body, and very soft ones don't support a growing back. Every mattress page here shows its firmness on the same scale, so you can compare like with like. Our kids mattresses page explains more.
Foam or springs?
Both work well for children. Foam mattresses are light and quiet, which helps when you're lifting a corner to change the sheets every week. Pocket sprung mattresses let more air through, which suits children who get warm at night. What matters most is the firmness and a snug fit.
Protect it from day one
Accidents happen, especially in the first months in a big bed. A waterproof mattress protector under the sheet keeps the mattress clean and costs far less to replace. Choose a breathable one, so the bed doesn't feel hot or crinkly. Some children's mattresses also have a wipe-clean cover. See mattress protectors and waterproof mattresses.
Making the first nights easier
- If the room allows, put the new bed where the cot bed was, so the view from the pillow is familiar.
- A bed guard can help while they get used to the extra space. Check its age guidance before you fit it.
- Let them choose the bedding. It's a small thing that gets a lot of children excited about their new bed.
If it's a bunk or a high sleeper
Keep them off the top bunk until they're 6, and choose a mattress that sits at or below the maximum mattress line on the frame. Our bunk bed safety checklist covers the rest.