How To Fill Gaps Between The Crib & Mattress [Safely And Easily]

In some cases, you may end up with a gap between the crib and mattress. This has probably led you to wonder how to fill the gap safely and easily. Look no further. We have researched all about what options you have when it comes to filling the gap between a crib and mattress and have the answer for you.

There are a few ways people can fill the gap between their crib and mattress, but the safest, easiest, and most reliable way is with a pool noodle or by attaching a board to the crib itself. The best thing to do is to buy a new crib mattress that does not have more than one inch of a gap all the way around.

You might be asking yourself more questions about your baby's crib. If you would like to learn more about what size a crib mattress is, how to tell if your crib mattress is too small for the crib you have, or how old a crib can be and still be safe, keep reading this post to find out.

empty-baby-crib-mattress-bed yellow pillow case, How To Fill Gaps Between The Crib & Mattress [Safely And Easily]

Should There Be A Gap Between Mattress And Crib?

While crib mattresses are made to be a little smaller than the crib, there really should not be more than a gap of one inch. Babies have gotten their head, arm, or leg stuck in this space. That is why it is extremely important that you fill the gap in a safe and effective manner.

If you are not going to replace the mattress and need to fill the gap between your crib and mattress, attach a board to the crib structure.

Attach the board from the bottom of the crib so that the screws are only in the bottom part of the board. A pool noodle is the next best thing to fill the gap between the crib and the mattress. 

More Options For Securing A Crib Mattress

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Foam or a tube that is the right size wrapped in something soft will work too. Whatever you use should be firm to avoid being a suffocation hazard.

Some people have rolled up a blanket or a towel and firmly stuffed it into the gap between the mattress and crib. Do not do this if you feel there is a chance of your baby getting ahold of it. A baby who is not rolling over yet is not capable of grabbing a blanket and pulling on it.

If your baby is over one year old, you may consider switching to a toddler bed with less of a gap between the mattress and frame. Blankets and towels are a suffocation hazard if they end up inside of the crib. A video baby monitor is ideal so that you can see your baby at all times, but that is not foolproof.

Click here to see this video baby monitor on Amazon.

Do not bind the blanket or towel with rubber bands or twine or anything like that. The reason you should not bind it is because that could add a new risk for your baby.

Taking the risk of your baby accidentally getting ahold of rubber bands or whatever else you could bind a blanket or towel with is not worth posing a choking hazard.

It is best to avoid blankets or towels whenever possible when it comes to a baby. Choose a safer alternative if you have the option.

What Size Is A Crib Mattress?

The standard size of a crib mattress is 52 inches long and 27.5 inches wide. The thickness of a crib mattress varies from four to six inches.


If the crib mattress is the right size for the crib that it is in, it should fit snugly. You can lift the mattress out of the crib and set it down vertically to put the fitted sheet on.

Once the fitted sheet is on, then you lay the mattress down. There should not be a gap bigger than what you can fit two fingers in between the railing and mattress.

Click here to see this standard crib mattress on Amazon.

Having the right size crib mattress eliminates the risk of your baby getting injured or dying because of a gap. Secure whatever you fill the gap with or get a new crib mattress.

How Do I Know If My Crib Mattress Is Too Small?

Put your fingers in the gap, and see how many fingers you can fit in that space. If the answer is more than two, then your crib mattress is too small. You should order a new one that is the correct size if you want to be able to use the crib safely.

How Do I Know If My Crib Mattress Is Firm Enough?

A crib mattress that is too soft can lead to your baby suffocating. It is not worth the risk. In order to create the safest sleep environment possible for your baby, you need to have a firm mattress in their crib for the first year of life. The firmer, the better.


Whenever you push your hand down on a crib mattress it should firm back up quickly. If it does not go back to normal quickly, then it might not be the right crib mattress for your baby.

You have a natural instinct to want your baby to be comfortable. To you, a soft mattress is comfortable, but for a baby, they need a firm mattress.

Is A Toddler Mattress The Same Size As A Crib Mattress?

Yes, a crib mattress is the same size as a toddler mattress. A toddler mattress is softer than a crib mattress. You can use the same mattress in your crib and toddler bed if needed.

If you have a convertible crib, then it has the capability of being turned into a toddler bed. You can often use the same mattress when you do this since the frame is the same size either way. Some crib mattresses are made so that you can flip them over to the side that is not as firm after your baby is one year old. 

What Size Bed Should A Two-Year-Old Have?


The age of two is a pivotal moment in a toddler's life. At this point, many parents switch over to a toddler bed instead of a crib.

You can use a crib a little longer than that if you do not think the child is ready or you are not ready. It works vice versa as well; if you have a rambunctious 17-month-old who likes to climb out of their crib, you may want to think about switching to a toddler bed a little sooner.

How Long Can My Toddler Sleep In A Crib?

Your toddler can sleep in their crib for up to three years. If you have not made the transition from crib to toddler bed by age of three, it is probably the time to do so.

The majority of toddlers are transitioned from a crib to a toddler bed somewhere between the age of 18 months and 36 months. Some time between your child's third and fourth year is perfectly fine. Every child is different.

If your child is three years old but is going through a transition in their life such as a new preschool or daycare, parenting separating or divorcing, a recent move, or any big change, you may want to wait a little longer to transition them.

Do what is right for your child depending on if they appear ready for the transition.


We say three years old is the age for transitioning your toddler from their crib, but you know your child best.

Convertible cribs make it possible to transform the crib into a toddler bed. This can help the transition for some toddlers because the environment still looks very similar from the position of laying down.

Click here to see this convertible crib on Amazon.

How Old Can A Crib Be And Still Be Safe?

It is said that a crib can be as old as 10 years before it is considered to be too old. Crib railings have the potential to crack. The metal under the mattress could rust or wear out. Safety standards change a lot within 10 years as well, so this is something to keep in mind. A new crib is best.

If you buy a used crib or are given a crib, you should ask how old it is or how long it has been in use. This will help you gauge whether or not it is safe for your baby. It's a good idea to inspect all parts of a used crib before deciding to use it.

In Closing

empty-baby-crib-mattress-bed yellow pillow case

While there are several options for how you can fill the gap between a crib and mattress, some are safer alternatives than others. You truly should not use a towel or blanket unless it is a very temporary solution.

An affixed board is the best option, and a pool noodle is the other go-to option. Regardless, if there is more of a gap than two of your fingers fit in or more than an inch wide between the crib and mattress, you should order a new mattress that is the correct size. 

Before you go, check out the following links that you might be interested in:

11 Country Crib Bedding Sets for That Rustic Nursery Look

What To Put In Baby Bath Caddy [10 Essential Items]

8 Adorable Ladybugs Crib Bedding Sets

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