When to Flip a Crib Mattress: The Best Time To Do It

A crib mattress is usually designed with 3 layers: a soft layer, a middle layer, and a firmer one. The soft side is commonly referred to as the toddler side and the firm side as the infant side. Newborns sleep on the firmer side of the mattress. Once they are old enough, the mattress can be flipped so they can sleep on the softer side. But when is the best time to flip the crib mattress?

The best time to flip a crib mattress is when the baby is 12 months old. At that age, the baby would have developed stronger muscles and is considered a toddler.

The rest of this article explains the best time to flip the crib mattress, why the mattress should be flipped, why the newborns sleep on a firm mattress, and other related questions.

What is a crib mattress?

A crib mattress is, as the name says, a mattress put in a crib. It is usually made of thick foams or a combination of foam and gel, designed to help newborns sleep on their backs. Since newborns are fragile, it is very important to put them on a firm mattress as opposed to a soft bed. This helps to provide adequate support to their spines and bones. When the infants are old enough to be placed on a mattress of their own, the crib mattress should be replaced to ease their transition into a bed.

Why flip the mattress?

You may notice that newborns sleep on a firm mattress in the crib while toddler beds usually have a soft mattress. This is because when the crib mattress is ‘stiff’, newborns are not able to move on it. This helps prevent the infants from rolling from side to side and also avoids mishaps like SIDS (Sudden Infant Death Syndromes). However, when the baby is grown and becomes a toddler (12 months old or more), they are able to move on their own. At this stage the baby can become unconfortable with the firmness of the mattress. If your baby starts waking up frequently during sleep, it is an indication that she started hating the firm side of the crib mattress. This is time to flip the mattress and let the baby sleep on the softer side.

Another reason to flip the mattress is to make the transition from crib to mattress easier. Once the baby starts moving around the crib on her own, it is time to move her to her own mattress.

However, the transition from a crib to a mattress is a big change for the baby which can make her sleep uncomfortable. So to make this transition easier, the crib mattress is flipped and the toddler is let to sleep on its softer side. Letting the toddler sleep on the softer side helps her to be comfortable when moved to a mattress.

When to flip the mattress?

The first thing is that the baby should stay on the firmer side of the crib mattress. Babies shouldn’t be forced to change their sleeping positions and they are usually scared to wake up from the position they are in. The baby also shouldn’t be left on the softer side, not because they are uncomfortable but because they may suffocate.

However, when the baby grows up to be a toddler, it is time to flip the crib mattress. Once the baby is 12 months old or more, she is safe to sleep on the softer, toddler side of the crib mattress.

How do I know which side my baby’s mattress is?

The sides of a 2-stage crib mattress are marked with the words “soft” or “firm.” If the one you have doesn’t have any tags sewn into them stating which side is what, you can identify the soft and firm sides by pressing on it. When you apply pressure,the firmer side will snap back faster while the softer side is slow to regain its original shape.

How firm is the firmer side of the crib mattress?

On a scale of firmness mattresses can be divided into four: soft, medium soft, medium firm and firm. For newborn the firm side of the crib mattress should be the firmest available in the market. Based on the firmness scale of ten, its firmness should be 8 to 10 (Source). The softer side of a two-stage crib mattress should fall into the medium firm category with a firmness value of 5 to 7 on a scale of 10.

Examples of 2-stage crib mattresses

Here are two good 2-stage crib mattresses (crib mattresses with a soft side and a firm side);

Sealy Baby Flex Cool

Sealy baby flex cool crib mattress

Sold by Sealy, this 2-stage baby crib mattress has 204 premium coils to provide maximum firmness to support newborns. In addition, the mattress is waterproof while at the same time its cover is breathable too to prevents any chance of suffocation. This mattress is Greenguard Gold certified which means it has no chemical emissions that can harm your baby.

Naturepedic Breathable Organic Crib Mattress

Naturepedic Breathable Organic Crib Mattress

Naturepedic is another popular company in the USA that makes mattresses. This crib mattress by them is another good example of a 2-stage mattress. It comes with a breathable, 3D mesh cover as well as a waterproof mattress which is also fire-resistant. It also has Greenguard certification for being free of any chemical emissions.


If you are using a two-sided mattress it is recommended to flip it when the baby becomes a toddler. However, there is no harm in letting your baby sleep on the firmer side as long as she is confortable on it.

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