Children's Mattress: From Toddler Bed to Age 10
Partilhar
The switch from crib to big bed usually raises more questions than buying the crib itself. When to do it? What size? What firmness, if the child is still going to grow 40 cm? I'll answer in order.
When to move out of the crib
There's no exact age, there are signs. Most children make this transition between 2 and 3.5 years old, and the trigger is usually one of these:
- They start trying to climb over the rails — this is the safety signal and shouldn't be delayed.
- They've reached about 90 cm in height, or their head is less than 20 cm from the top of the rail.
- They're giving up night-time nappies and need to get up on their own.
- A sibling is on the way and the crib is about to change owners.
A practical tip: don't make this change in the same week as another major change — starting nursery, moving house, the birth of a sibling. Leave two to three weeks in between. Children's sleep absorbs one change at a time.
What size to buy
The temptation is to buy a small bed "their size". It's almost always money poorly spent: by age 7 it no longer fits.
The choice that makes sense for most families is to go straight for 90×190 cm, the standard Portuguese single bed size, or 90×200 cm if there's room in the bedroom. A 90×190 mattress stays with the child from age 2 through adolescence — and afterwards still works as a guest bed.
70×140 toddler beds have their place in very small bedrooms, or when the child feels anxious about large spaces. But they're a two- or three-year solution. The full size table is at mattress sizes in Portugal.
What firmness
Firmness medium to medium-high. Here the criterion differs from that for adults, and it's worth understanding why.
A child weighs little — between 12 and 35 kg in this range — and so sinks in very little. If the mattress is soft, they don't "activate" it: they stay on the surface and the spine ends up misaligned, without the support system ever coming into play. The surface should be firm and even, with a thin comfort layer.
Avoid a thick layer of memory foam for young children: it retains more heat, and children regulate temperature during the night less well than adults.
Materials and certifications
A child spends 10 to 12 hours a day in bed, with their face resting on the surface. Materials matter more here than at any other age.
- Oeko-Tex Standard 100 on the fabric and foams — guarantees the absence of harmful substances.
- Removable cover, washable at 60 °C. It's not a luxury: it's the temperature at which dust mites die.
- Good ventilation — open-cell foams or pocket springs.
- No persistent smell. Some odour in the first few days is normal and fades; if it persists after a week in a ventilated room, return it.
If there's asthma or rhinitis in the family, see anti-mite mattress and allergies.
Protection: the item that isn't optional
Between ages 2 and 6 there will be night-time accidents. It's normal development, not a problem. But urine soaks into a mattress in seconds, and a children's mattress without a protector lasts much less than it should.
Use a waterproof, breathable protector, with a fabric top layer and washing at 60 °C. A trick that saves nights: make the bed in two layers — protector, sheet, protector, sheet. At three in the morning you remove the top layer and the bed is already made underneath.
More at mattress protector: is it worth it.
Bed safety
- No gaps. The mattress should fit the frame without leaving side space where an arm or leg could get through. Under 2 cm of total gap.
- Low height. In the first few months, the lower the bed, the less scary a fall is. Some start with the mattress on the floor — a valid option, as long as the room is dry and the mattress is aired out regularly.
- Side rail for the first 3 to 6 months, until the child develops a sense of the bed's edge.
- Pillow — low and firm, and only from age 2 onwards. Not before that.
What I usually suggest
| Age | Solution | Note |
|---|---|---|
| 0–2 years | Suzu, Kotone or Mokuren crib mattress | Firm, flat surface, as recommended for safe baby sleep |
| 2–6 years | Hirune or Kumo (雲) in 90×190 | High-resilience foam, medium firmness, good ventilation, light to handle |
| 7–12 years | Kumo or Sora (空) in 90×190 | Keeps pace with weight gain without losing support |
See the baby collection and the full mattress range.
Questions I get asked
Can I use a hand-me-down mattress from an older sibling? You can, if it has less than 5 years of use, shows no visible sagging, and was used with a protector. If you don't know its history, it's not worth the risk.
They sleep better in our bed. Is it because theirs is bad? Almost never. It's usually about closeness, not firmness. Before changing the mattress, work on the bedtime routine.
When should you replace a child's mattress? Check annually. The trigger isn't the mattress's age, it's the relationship between the child's weight and the support: if at age 10 they start complaining of waking up poorly, reassess the firmness.
Isn't 90×190 too big at age 2? It seems that way, in the first week. It stops seeming that way by the third — and saves you a purchase at age 7.
"The most expensive mistake I see is buying a small toddler bed at age 2 and having to buy everything again at 6. Go straight for the 90×190 and the mattress will last through to adolescence." — Ana Cristina, Sleep Advisor
If the child has scoliosis, diagnosed allergies or another clinical condition, talk to the paediatrician before deciding on firmness.
How to decide
Confirm there are signs of readiness to leave the crib. Choose 90×190 if the room allows it. Medium to medium-high firmness, cover washable at 60 °C, waterproof protector on top. Side rail for the first few months.
If in doubt, call me on +351 21 150 95 04.
