What Makes a Safe Baby Bed? A Guide from Crib to Toddler Bed

Craft Paper Co.

Sep 18, 2026

nursery kids' room safe sleep guide choosing a bed

Convertible crib in a nursery, on a wall away from the window, with light green tree and cloud wallpaper behind it

Short answer: A baby's mattress should be firm, flat and fit the crib with no gaps, and there should be nothing in the crib except the mattress and a fitted sheet. For a baby, the only criterion is safety. For a toddler bed, the criterion is timing: once your child starts climbing out of the crib or is taller than 89 cm (35 in), it's time for a low toddler bed, which usually happens somewhere between 18 months and 3 years. The top bunk of a bunk bed isn't used before age 6. The crib's style, color, wood and the wall behind it all come after these two rules are in place.

When parents set up a nursery, the decision that usually takes the most time is the crib model, yet what matters for a baby's health is the mattress inside the crib and what surrounds it. In this post we answer, one by one, the questions we hear most often from families in our eight years of making things for baby and kids' rooms at Craft Paper Co., based on international safe sleep guidelines. We make wallpaper, not mattresses, so you won't find any brand or model recommendations below. What you will find is what to look for when you're looking at a bed.

1. What makes a safe baby mattress? Firm, flat and gap-free

All the major guidelines on infant sleep (the American Academy of Pediatrics' 2022 recommendations, the UK's NHS and The Lullaby Trust) come down to the same three words: firm, flat, snug-fitting.

Firm: The mattress shouldn't dip when you lay your baby on it. The Lullaby Trust's measure: your baby's head shouldn't sink in more than a few millimeters. A soft mattress that looks "comfy" to an adult isn't safe for a baby; if a baby rolls onto their tummy, a firm mattress keeps their face from sinking in.
Flat: Inclined sleep products (mattresses that raise the head, rocker-style sleep nests) are not recommended. The American Academy of Pediatrics draws the line at 10 degrees: no surface inclined more than that is considered safe for infant sleep.
Gap-free: The mattress should fit the crib exactly. A practical test: if you can fit two fingers between the mattress and the side of the crib, the mattress is too small. The European standard sets an upper limit of 3 cm (about 1.2 in) for this gap. That's why a mattress is bought to the crib's inside measurements; "roughly the same" isn't good enough.

Then there's a waterproof cover: according to The Lullaby Trust, the safest mattress is firm, flat and has a waterproof cover, which is easy to keep clean because you can wipe it down. On top of the cover goes a thin, well-fitted sheet, and nothing else.

What belongs in the crib? Only the mattress and a sheet

Pillows, duvets, blankets, bumpers, stuffed toys: none of these belong in the crib in the first year. The reason isn't how it looks; it's the risk of your baby's face being covered or of getting trapped. To keep a baby warm, use a season-appropriate sleep sack instead of a duvet; weighted blankets and weighted sleep sacks are not recommended. The NHS range for room temperature is 16–20 °C (61–68 °F).

This rule surprises new parents, because the cribs in store displays show exactly the opposite: pillows, tulle, padded sides. A display is set up to look pretty; no baby sleeps there.

2. The crib: full-size crib, play yard or bedside bassinet?

This is the question parents are most torn about. All three can be the right product; the difference is how long you'll use it and where it will sit in the room.

Type	Typical size (cm)	How long it's used	Watch out for
Bedside bassinet / Moses basket	40×90, 50×90	The first months	Even if the mattress sits level with the parents' bed, it must be a separate sleep surface; the baby isn't brought into the parents' bed
Play yard (travel cot)	60×120, 70×120	Up to 2–3 years (check the manufacturer's weight limit)	Mesh sides should be sturdy and the mattress should be the play yard's own; no second mattress is added on top
Wooden crib	60×120, 70×130, 70×140	Until your child climbs out; convertible models extend to 160–180 cm (63–71 in)	Slat spacing, mattress base height and hardware (see below)
Montessori floor bed	70×140, 80×160, 90×190	Once your child is walking (about 18 months+)	Not suitable under age 1; the whole room must be childproofed

The guidelines agree on this: for at least the first 6 months, a baby sleeps in the same room as the parents, but on a separate sleep surface. So the "bedside" idea is right; the "in the parents' bed" idea isn't. That's why a small bassinet or play yard usually stays in the parents' room in the early months, and the crib in the nursery really gets to work after about 6 months.

What to check on a wooden crib

In Europe, cribs are made to the European standard EN 716 (adopted in Türkiye as TS EN 716); it's enough to ask the seller to confirm compliance. The standard has three points you can measure yourself as a parent:

Slat spacing: roughly 4.5–6.5 cm (1.8–2.6 in). Wider gaps can trap a baby's head. (The US rule of thumb says the same thing as "a soda can shouldn't fit through.")
Side height: with the mattress base in its lowest position, there should be at least 50 cm (about 20 in) from the top of the mattress to the top of the side. Once your baby starts sitting up on their own, lower the base to its lowest position.
Protrusions and hardware: corner posts shouldn't stick up (clothing can catch on them), and screws should all be there and tight. With a secondhand crib, checking for missing parts and recalls is a must.

A note: in the US, drop-side cribs have been banned from sale since 2011, because gaps created when the mechanism came loose led to serious accidents. Europe hasn't banned them, but the standard tightened the requirements for the locking mechanism. If you have an old family crib, this is the first place to look.

What parents choose and why, and what gets overlooked

In online forums and in our conversations with customers, the same choices come up again and again for the same reasons. None of them is wrong, but each comes with a trade-off worth knowing up front.

Choice	Why parents choose it	What gets overlooked
Play yard	Portable, folding, affordable; it moves to the living room and goes on vacation	It has a weight limit and is usually outgrown at 2–3 years; mesh sides loosen over time; because its own thin mattress is firm, parents add a second mattress on top "so the baby is comfortable", which is exactly what shouldn't be done
Bedside bassinet	Easy night feeds, baby within sight	It only lasts a few months; the side attached to the parents' bed must leave no gap; once the baby grows, you still face the cost of a second crib
Rocking cradle	Makes it easier to get the baby to sleep	Rocking becomes a sleep habit and makes the move to a stationary bed harder; the rocking base needs to lock and should be fixed in place once the baby starts sitting up
Convertible crib	"We buy it once and use it for years"	Once extended, finding a mattress that fits gets harder (in-between sizes like 70×140 → 70×160); at 3–4 years a child finds a 70 cm (about 28 in) width narrow; the climbing risk continues during the in-between stage with rails
Montessori floor bed	No falls, the child gets in and out on their own, the room looks lovely	Not suitable under age 1; the child gets up at night and wanders the room, so the whole room has to be safe; sleeping close to the floor is cold in winter; because the mattress sits on the floor, air doesn't circulate underneath and moisture and dust build up
Bumper and pillow set	"So they don't bump their head on the slats", and to look like the store display	These are exactly the things the guidelines say to keep out of the crib in the first year; a crib with standard-compliant slat spacing doesn't need a bumper
Hand-me-down mattress from an older sibling	Saves money; "it was used for two years, it's as good as new"	A new mattress is recommended for every baby; if you do use one, its waterproof cover should be intact and the mattress itself shouldn't sag or be torn

Common myths

"A soft mattress is more comfortable, so the baby sleeps better." True for adults, the opposite for babies. A baby's mattress should be firm; comfort comes from clothing, room temperature and routine, not from a soft mattress.
"Without a pillow their head will get flat / their neck will hurt." Pillows aren't used in the first year. What protects head shape isn't a pillow but supervised tummy time while awake during the day and regularly changing the direction of the baby's head.
"A bumper protects the baby from the slats." In a standard-compliant crib the slat spacing is already safe; a bumper is one of the soft objects the guidelines don't want in the crib.
"If their head is raised, they won't have reflux." Inclined sleep surfaces (more than 10 degrees) are not recommended for babies; if you suspect reflux, the answer isn't tilting the mattress but talking to your pediatrician.
"They'll get cold, let's add a duvet." Use a season-appropriate sleep sack instead of a duvet or blanket; weighted sleep products are not recommended either.
"If I buy a breathing monitor, I'll feel at ease." The American Academy of Pediatrics says consumer heart rate and oxygen monitors used at home are no substitute for safe sleep; the real protection is the rules above.
"An expensive crib is safer." Safety isn't set by price but by compliance with the standard and how well the mattress fits the crib. If a simple crib meets both, it's enough.

3. Mattress materials and labels

The guidelines don't answer the "foam, innerspring, coconut fiber or latex?" question for a baby mattress; as long as it's firm and flat, they're all acceptable. What the guidelines focus on is what the mattress gives off.

A study published by the University of Toronto in 2025 showed that 16 new baby mattresses sold in North America released 21 different semivolatile chemicals, some of them flame retardants, and measured noticeably higher exposure where the baby sleeps than elsewhere in the room. The study's practical advice is simple: wash sheets often, keep the number of items in the crib down, and let a new mattress air out for a few days after taking it out of its packaging.

This topic isn't new to us; we ask the same question about wallpaper ink. Every large surface that comes into a room (mattress, rug, furniture, wall) either gives something off or it doesn't, and because a baby breathes much more air than an adult relative to body weight, the difference matters more for them. Three things on a mattress label are meaningful in this respect:

OEKO-TEX Standard 100, Class I: for textiles; Class I has the strictest limits, for baby products up to 36 months. Check it for the mattress fabric and cover.
CertiPUR-US: for foam only; it means the foam is screened for heavy metals, certain flame retardants and formaldehyde. An innerspring or fiber mattress won't carry this label, and doesn't need to.
UL GREENGUARD Gold: shows that a product has low chemical emissions into indoor air; the "Gold" level is defined for sensitive environments like schools and nurseries. It's also the certification our printing inks carry.

"Organic", "natural" and "healthy" are not certifications. If there's no certificate name and number on the label, those words are marketing copy.

Secondhand mattresses

A crib can be bought secondhand; the same can't be said for a mattress. A case-control study from Scotland, published in the BMJ, suggests that used mattresses from another household may carry more risk for babies; the study doesn't prove cause and effect, but The Lullaby Trust's advice is clear: a new mattress for every baby. If you do use a hand-me-down mattress from an older sibling, its waterproof cover should be intact and the mattress itself shouldn't sag or be torn.

4. When do you move from a crib to a toddler bed?

There's no magic age; there are three signs:

Climbing: the day your child tries to climb over the side, the crib is done. Falling over a crib side (from about 130 cm, or 51 in) is much riskier than falling out of a low toddler bed (about 60 cm, or 24 in).
Height: the American Academy of Pediatrics' limit is 89 cm (35 in), or when the side height is less than three-quarters of your child's height.
The side is at chest level: if the crib side reaches your child's chest when they stand, it's now easy for them to fall.

These three signs usually show up between 18 months and 3 years. An in-between step you can try before buying a new bed: put the crib mattress on the floor. Your child gets used to sleeping close to the floor, and the fall distance drops to zero. At the same time, set up the rest of the room for a child who may get out of bed and wander at night: anchor the dresser and bookcase to the wall, cover outlets and put a gate at the top of the stairs.

Is a Montessori floor bed a good idea?

It's a good option for a child who walks; it builds independence and there's no falling problem. On two conditions: it isn't used under age 1 (the guidelines call for a standard-compliant crib for babies), and the whole room must be childproofed, because your child may get up and wander at night. There's one more practical point parents often mention: a floor bed is cold in winter; a rug or a low raised platform solves that.

Toddler and kids' bed sizes

Common sizes in Türkiye (sizes vary by country): 70×140 and 80×160 cm (junior) for ages 2–5, and 90×190 or 90×200 cm (single) for school age. Models sold as "convertible cribs" extend from 70×140 to 160–180 cm; a sensible in-between option for small rooms. In the long run, the most economical route is usually to move straight to a single bed at around age 3 and add a removable bed rail. Manufacturers generally design bed rails for ages 2–5; they aren't used on cribs or for children under 2.

What age for a bunk bed?

The limit for the top bunk is age 6. In the US this is a warning that must be printed on bunk beds, and the European standard EN 747 uses the same age. The top bunk needs guardrails on both sides, with the rail at least 16 cm (about 6.3 in) above the top of the mattress (a thick mattress makes the rail shorter), a fixed ladder, and a one-child-only rule. Loft beds follow the same rule.

5. Where should the bed go in the room?

Low toddler bed with a guardrail; animal wall decals and a hand-painted moon on the wall above the head of the bed, window on another wall — The wall at the head of the bed: no frames or shelves above it, the pattern is on the wall itself. The window is on another wall, and the bed is low with a guardrail.

Away from the window. The American Academy of Pediatrics puts it plainly: a crib or any other child's bed doesn't go next to a window. The reasons are drafts and sun, and also curtain and blind cords: cords are a serious strangulation hazard for young children, which is why consumer safety agencies recommend keeping beds away from windows. Cordless window coverings are safest; if there is a cord, it should be completely out of reach of the bed.
Away from radiators and direct sunlight. Babies are more sensitive to heat than adults and can't tell you they're sweating; that's why the guidelines recommend keeping the room cool (16–20 °C, or 61–68 °F) and placing the crib away from heat sources. Radiators have one more effect: in winter they dry out the air in the room, and dry air irritates a baby's nose and throat. A small hygrometer in the room takes the guesswork out of this; the general advice is to keep humidity between 30–50%. If it drops below that range, a cool-mist humidifier helps (the American Academy of Pediatrics recommends cool-mist rather than warm-mist because of the risk of burns). Two conditions: the device should be emptied and cleaned every day, because bacteria and mold grow in standing water, and humidity shouldn't go above 60%; if you see condensation on the windows, it's too high. Place the humidifier away from the bed and up off the floor; if humidity is already in range, you don't need one at all.
Visible from the door and easy to reach. This isn't a safety rule, just practical advice: when you come into the room at night, you should be able to see your baby without turning on the light and reach the crib easily.
Nothing should hang above the crib. The guidelines say a mobile should be securely attached and removed once your baby starts pushing up on hands and knees (around 5 months). We take this one step further and suggest keeping heavy frames, shelves and mirrors away from above the crib as well; that's our own view, not a guideline. If the wall needs some decoration, the safest way is to give the wall itself a pattern instead of hanging something: a wallpaper mural, or flat wall decals that won't fall or come apart in pieces.

One last detail for little ones: if you're using a floor bed or a low bed, wall decals should be placed higher than your child can reach, so they can't peel them off and put them in their mouth. Wallpaper doesn't have this problem.

Don't buy without asking the seller: 6 questions

Is the mattress firm? Press it with your hand; if it dips easily, it isn't for a baby.
What are the crib's inside measurements, and does the mattress match them exactly? Do the two-finger test.
Does the crib comply with EN 716 or your local crib safety standard? Is the slat spacing over 6.5 cm (2.6 in)?
Does the mattress have a waterproof cover, and can it be removed and washed?
Which certification is on the label: OEKO-TEX Class I, CertiPUR-US, GREENGUARD Gold? Can you see the certificate number?
If it's a convertible crib: what mattress size will you need once it's extended, and can you actually find that mattress?

Frequently asked questions

Should a baby mattress be firm or soft?

Firm. The mattress shouldn't dip when your baby lies on it, and their head shouldn't sink in more than a few millimeters. A soft mattress raises the risk of a newborn's face sinking in if they roll onto their tummy. With "double-sided" mattresses, use the firm side in the first year.

Until what age is a crib used?

Until your child starts climbing out of the crib or is taller than 89 cm (35 in); this is usually between 18 months and 3 years. It's climbing and height that decide, not age.

Play yard or crib?

Both can be safe. A play yard is portable and used up to 2–3 years; a wooden crib lasts longer and comes in convertible models. The rule is the same for both: its own mattress, a snug fit, and nothing else inside.

At what age can a child use a Montessori bed?

Once they're walking, usually from about 18 months. A floor bed under age 1 doesn't fit with safe sleep guidelines. The room must be fully childproofed.

At what age can a child use a bunk bed?

The top bunk isn't used before age 6. The bottom bunk is fine for younger children.

Once you know where the bed goes, it's time for the wall above it. Our hand-drawn wallpaper murals, made to your room's exact size, and our wall decals that come off without damaging the wall are the simplest way to make the room feel warm without hanging anything above the crib.

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