What Size Mattress Does a Child Need? Sizes in cm by Age

It usually starts with a growth spurt. One month your child fits perfectly in their cot, and the next their feet are pressing against the rail every night. If you’re standing in a UAE furniture showroom trying to work out the right kids mattress size and comparing the mattress size for kids by age, whether you need a 70x140cm mattress or a full 90x190cm single, you’re not overthinking it mattress sizing genuinely changes a lot in the first decade of a child’s life, and getting it wrong means either a cramped sleep or an oversized bed swallowing a small bedroom.

For parents comparing mattress size for kids by age, the key is to look at more than just the number on the age range. Your child’s height, bedroom space, bed frame and expected growth all play a role in choosing the right mattress.

The good news is that mattress sizing for kids follows fairly predictable stages. Here’s how it breaks down.

Kids Mattress Size Chart by Age

Age Group	Bed Type	Typical Mattress Size (cm)
0–2 years	Cot / Crib	60 x 120
2–4 years	Toddler / Junior Bed	70 x 140 or 80 x 160
4–7 years	Single (small)	90 x 190
7–12 years	Single (standard)	100 x 200
12+ years	Single or King Single	120 x 200

A children’s mattress size chart is a useful starting point when you’re comparing mattress dimensions by age. However, age alone should not determine the final choice, since your child’s height, room size, bed frame and expected growth also matter.

A few things worth noting about this chart. First, these are typical ranges, not hard rules a tall six-year-old may already need a standard single, while a smaller nine-year-old might still be comfortable on one. Second, once a child moves past the cot stage, most UAE parents skip the “junior bed” size altogether and go straight to a 90×190 or 100×200 single, simply because it lasts years longer and doesn’t need replacing again in 18 months. It’s a reasonable shortcut if your child’s room has the floor space for it.

The crib-to-toddler transition (60×120 to 70×140) tends to happen earliest, often triggered by a child climbing out of the cot rather than by age alone. The bigger jump toddler bed to single is the one parents plan around, usually timed with a move to a “big kid” room or the start of school.

When using a children’s mattress size chart, look at the recommended dimensions alongside your child’s current height and sleeping habits. This helps you avoid choosing a mattress that feels too small within a short period.

What to Consider Beyond Your Child’s Age

Age gives you a starting point, but three other factors matter just as much when you’re choosing a mattress size.

Room size. A standard single mattress at 100x200cm needs roughly a 3-square-metre footprint once you add the bed frame and a bit of clearance to make the bed. In smaller UAE apartment bedrooms, some families choose to stay on the 90×190 size a year or two longer simply because it fits the room better alongside a wardrobe or study desk.

Bed frame type. If you’re buying a bunk bed, the two mattresses don’t have to match. It’s common for the bottom bunk to hold a standard single while the top bunk uses a slightly narrower size for safety and weight reasons always check the bed frame’s recommended mattress dimensions before buying separately.

How long you want it to last. A mattress sized for exactly where your child is now might need replacing within two years. Many parents in the UAE buy one size up a 100×200 instead of a 90×190 to buy a bit more runway before the next upgrade, especially once a child is past age seven and growth becomes harder to predict.

None of this means you should oversize dramatically. A mattress that’s too large for the bed frame or the child’s current size can actually reduce sleep comfort and make the room feel cluttered rather than functional.

Frequently Asked Questions

What mattress size is best for a toddler bed?
Most toddler or junior beds are designed for a 70x140cm mattress, though some UAE brands offer 80x160cm as a slightly roomier alternative for the same bed frame category.

When should I move my child from a cot to a single mattress?
There’s no fixed age — it’s more about when your child starts climbing out of the cot or simply looks cramped. Many parents make the switch anywhere between age two and four, moving to a toddler bed first before a full single a few years later.

Is a single mattress too big for a young child’s room?
Not usually. A 90x190cm single fits comfortably in most standard UAE bedrooms and gives a child several extra years of use compared with a toddler-sized mattress.

Can two siblings share a bunk bed with different mattress sizes?
Yes, as long as each mattress matches what the bed frame’s manufacturer recommends for that level. Always check the frame specifications rather than assuming both bunks take the same size.

Finding the Right Fit

Mattress sizing for kids isn’t something you need to get perfectly precise a rough sense of your child’s current stage, their room size, and how long you want the mattress to last will get you to the right decision most of the time. If you’re furnishing a kids’ room from scratch or upgrading a single piece, browsing sizes side by side in person often makes the decision easier than guessing from a chart alone something worth keeping in mind if you’re near our Dubai showroom or shopping the collection online across the UAE. Choosing the right kids mattress size becomes easier when you consider your child’s age, current height, room space, and how long you want the mattress to last.

A children’s mattress size chart can make the decision much easier, especially when you’re comparing cot, toddler, junior and single mattress options. Use the chart as a guide, then consider the available bedroom space and how long you want the mattress to last.