Kids mattresses

Most children sleep well on a medium to medium-firm mattress that fills their bed frame without gaps and, on a bunk or high sleeper, sits at or below the maximum mattress line. Every one here meets UK fire safety rules (BS 7177).

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What size mattress does a child need?

A child needs whichever mattress size their bed takes: 140 x 70 cm for a cot bed or most toddler beds, and usually a single, 90 x 190 cm (3ft x 6ft3), for a first big bed, bunk or high sleeper. Age matters less than the frame.

Bed Mattress size Good to know
Cot bed or toddler bed 140 x 70 cm Most toddler beds share the cot bed size
Shorty bed or shorty bunk 75 x 175 cm (2ft6 x 5ft9) Narrower and shorter than a single
Small single bed 75 x 190 cm (2ft6 x 6ft3) Found on some cabin beds and in box rooms
Single bed, bunk or high sleeper 90 x 190 cm (3ft x 6ft3) The most common size for children
Many beds from European brands 90 x 200 cm (3ft x 6ft6) Same width as a UK single, 10 cm longer

Many children move from a cot bed to a single somewhere between 18 months and 3 years, but there's no fixed age. Whichever bed it is, measure the inside of the frame before you order rather than going by the bed's name. A mattress that's slightly too small leaves a gap, and on a child's bed that's a safety issue. For babies under 12 months, follow the Lullaby Trust's safer sleep advice: a firm, flat, waterproof mattress in good condition that fits the cot snugly.

How firm should a child's mattress be?

A child's mattress should usually be medium to medium-firm, which is 5 to 8 on our 1 to 10 firmness scale. That range supports a growing back without feeling hard to a light body. Toddlers are the exception: they need a firm, flat mattress.

Once children are past the toddler stage, very firm mattresses (9 or 10 on the scale) often feel hard to them, because a light body barely sinks in. Very soft ones aren't supportive enough. Within the medium to medium-firm range, go towards medium for a child who sleeps on their side, and towards medium-firm for a heavier child or one who sleeps on their front.

Brands don't share a firmness scale, so compare numbers within one shop rather than labels between shops. Every mattress page here uses the same 1 to 10 scale, so a 6 on one children's mattress means the same as a 6 on another.

Which type of mattress is best for kids?

No single type of mattress is best for every child: foam, pocket sprung, open coil and hybrid mattresses all work if the feel is medium to medium-firm and the depth suits the bed. The real differences are weight, airflow and cost.

  • Foam: light, quiet and spring-free, so it's easy to lift on a top bunk or high sleeper. Reflex foam feels springy; memory foam moulds to the body and can feel warmer.
  • Pocket sprung: each spring moves on its own and air moves between them, which suits children who sleep warm and older, heavier children.
  • Open coil: lighter and cheaper than pocket springs, and sensible for a spare bed that mostly sees sleepovers.
  • Hybrid: pocket springs with a foam comfort layer on top, giving airflow underneath and a softer surface.

Memory foam suits children who don't run hot, as long as the mattress is supportive overall. We never suggest memory foam for babies under 12 months.

What else matters in a children's mattress?

Beyond size and feel, a children's mattress should be easy to keep clean, let air move, fill the frame snugly and meet UK fire safety rules (BS 7177). Every mattress we sell meets BS 7177, so the other three are the ones to check.

  • Easy cleaning: a removable, washable cover or a waterproof protector copes with spills and night-time accidents. A waterproof mattress has the waterproof layer built into the cover, so there's nothing to forget.
  • Airflow: springs let air circulate, and natural fillings such as wool help regulate temperature.
  • A snug fit: no gaps at the sides or ends where an arm or leg could slip down.

What mattress does a bunk bed or high sleeper need?

A bunk bed or high sleeper needs a mattress that fits the frame and is no deeper than the maximum mattress line marked on the bed, which on many raised beds allows 15 to 16 cm. Plenty of ordinary mattresses are deeper than that.

Under BS EN 747, the line keeps the guard rail at least 16 cm above the top of the mattress, and the upper bed isn't suitable for children under 6. Mid sleepers and cabin beds have a maximum mattress line too, marked on the frame or given in the instructions. Toppers count towards the depth, and a lighter mattress is easier to lift when you change the sheets up high. Our bunk bed mattresses and high sleeper and cabin bed mattresses pages cover sizes and depths for each.

For the size most school-age children sleep on, see our kids single mattresses, and when a child starts to outgrow theirs, our teen mattresses page covers the extra support and length many teenagers need. We're parents ourselves, so if you're unsure which size, depth or firmness suits your child, ask us and we'll help you choose.

Written by the Mattress Town team. Last updated .

Kids mattresses: your questions answered

Can't see your question? Ask us and we'll get back to you.

Is memory foam good for children?

Memory foam can suit children over 12 months, as long as the mattress is supportive overall rather than soft. Memory foam moulds to the body and stays quiet, but it can feel warmer than springs, so a child who sleeps hot may be happier on pocket springs. For babies under 12 months, we never suggest memory foam.

What mattress should a 3 year old have?

A 3 year old needs a firm, flat, supportive mattress that fits their bed snugly: 140 x 70 cm if they're still in a cot bed or toddler bed, or 90 x 190 cm if they've moved to a single. Many children make that move between 18 months and 3 years. A washable cover or waterproof protector helps while they learn to stay dry at night.

Do children need a special mattress?

Children don't need a special mattress, but they do need the right one. Kids mattresses come in the same sizes as adult mattresses and are often lighter and slimmer, with a medium to medium-firm feel that suits a lighter body. On a bunk or high sleeper, the depth limit marked on the bed matters more than any label.

How thick should a child's mattress be?

On an ordinary bed frame, a child's mattress around 15 cm deep (about 6 inches) is usually enough, and standard mattresses run from about 18 to 25 cm. On a bunk bed, high sleeper or cabin bed, the mattress must be no deeper than the maximum mattress line, which on many raised beds allows 15 to 16 cm.

Can a child use a mattress topper?

A child can use a mattress topper on an ordinary bed, where it changes the feel, usually making it softer. A topper can't fix a sagging mattress, though. On a bunk bed or high sleeper, the topper counts towards the maximum mattress line, so the two together must stay at or below it. We never suggest a topper for a baby under 12 months.

What's the best mattress for a child who wets the bed?

For a child who wets the bed, the most practical choice is a waterproof mattress or a waterproof protector, so accidents stay out of the mattress and only the bedding needs washing. A waterproof mattress has the layer built into its cover; a protector comes off to be washed. Modern waterproof layers are quieter and more breathable than old plastic sheeting.

How often should you replace a child's mattress?

Replace a child's mattress when it sags, develops lumps or you can feel the springs, or when your child outgrows its size. There's no fixed number of years: an adult mattress typically lasts around 7 to 10 years, but a child moves on from a cot bed mattress much sooner. Rotating the mattress head to toe helps it wear evenly.

Are your children's mattresses fire safe?

Yes. All of our children's mattresses, like every other mattress we sell, meet UK fire safety rules for mattresses, BS 7177. When you check a child's bed for safety, also make sure the mattress fills the frame with no gaps, and that on a bunk or high sleeper it sits at or below the maximum mattress line.

Not sure which mattress?

Tell us about your bed and how you sleep, and we'll suggest a few that fit.

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