What to look for in a crib mattress


Babies spend a lot of time asleep during their first year — even though it may not feel that way to tired new parents! Since your little one will sleep an average of 12 to 14 hours per day for their first year of life, it only makes sense that parents-to-be wonder how to choose the best crib mattress.

What’s important to look for in a crib mattress that’ll (hopefully) get thousands of hours of use in the first twelve months? In addition to finding a crib mattress that fits your crib snugly and without gaps, you’ll want to consider factors such as materials, safety, firmness, and waterproofing, for those inevitable diaper leaks.

Below, we walk you through the most important crib mattress options to consider, and how the Cradlewise mattress stacks up.  

What are the different types of crib mattresses?

There are two main categories of crib mattresses:

  • Innerspring
  • Foam

Both types of mattresses are safe, but the materials and firmness can vary widely. Both innerspring and foam keep their shape well and support your baby’s sleep.

Innerspring crib mattresses

Innerspring mattresses are popular in the U.S. because they’re familiar — most of us adults grew up sleeping on innerspring mattresses, which are composed of metal coils and padding inside a structured frame. 

These mattresses have a higher price point and are heavier (because of the metal springs). Other factors such as the number of layers, and the quality of each layer, add to the price. 

Foam crib mattresses

Foam mattresses are typically made of polyurethane. They are usually lighter (5 to 13 lbs) than innerspring mattresses (15 to 30 lbs) and cheaper. 

You might be surprised to learn that foam crib mattresses can be just as firm and dense as innerspring mattresses. However, if a foam mattress is made with a higher density of materials, that most likely means a higher price. 

The Cradlewise mattress

Your Cradlewise comes with an organic crib mattress made from coconut coir and organic rubber latex. It’s closer in construction to a foam mattress than an innerspring due to the lack of metal coils, however, the Cradlewise mattress does not contain polyurethane. It is 100% organic and biodegradable.

How firm should a crib mattress be?

Firmness is perhaps the most important feature of a crib mattress. Parents should know that baby crib mattresses are specifically designed to be firmer than most adult mattresses, to minimize the risk of suffocation or Sudden Infant Death Syndrome (SIDS) in infants and young children that overly soft mattresses can cause.

The mattress firmness test is a critical standard developed by the Consumer Product Safety Commission (CPSC) to ensure that all crib mattresses sold in the United States meet certain firmness requirements. This test is performed using a specialized instrument called a “flat plate indenter,” which applies pressure to various areas of the mattress to measure its firmness. 

All crib mattresses sold in the U.S. comply with the standards of the CPSC’s mattress firmness test, and for safety reasons, parents should not use a non-standard mattress in their baby’s crib.  That said, crib mattresses are available in a range of firmness options, so you can choose what works best for your family’s budget, comfort, and peace of mind.

With innerspring mattresses:

  • The higher the coil/spring count, the better. Coil counts can range from 80 to 200. A higher number means the coils are closer together, making for a firmer mattress.
  • Border rods are also a plus and contribute to firmness. These rods are support rods around the edge of the mattress that help distribute your baby’s weight evenly.

With foam mattresses:

  • A higher density is equivalent to a high-coil count in an innerspring mattress.
  • High-density foam that can hold a higher number of pounds means a heavier, firmer core. 
  • The ideal foam mattress will have a foam core of approximately 1.5 lbs per cubic foot. 

Did you know?

A lot of crib mattresses have a softer side and a firmer side. Often, the firmer side is for newborns, and the softer side is for toddlers. These specifications should be made clear by the mattress manufacturer.

The Cradlewise mattress has a rubber latex side that is softer; the other side is slightly firmer. We recommend keeping the softer side up and using it for your little one, but both sides of the Cradlewise crib mattress pass the CPSC mattress firmness test.

What is the difference between a mini crib mattress and a standard crib mattress?

In the U.S., regular cribs are standardized by law, meaning they have to be 52 inches long and 28 inches wide. Mini cribs, on the other hand, do not conform to any specified size standards. 

So, when it comes to mattresses, most full-sized cribs have a standard crib mattress size. 

Since mini cribs can vary in size, they come fitted with a custom mini crib mattress. 

The Cradlewise mattress has been designed specifically to fit the dimensions of our Crib, and other mattresses cannot be used in it for safety reasons. The exact crib mattress dimensions are 37.6’’ x 23’’.

One frequently asked question we get is, ‘Why is your mattress so thin?”. It’s because we’re following ASTM standards (American Society for Testing and Materials).

To ensure the safety of newborns and infants, the ASTM has outlined a specific thickness for crib mattresses.

A thinner mattress lowers the risk of gaps between the crib’s frame and mattress which in turn reduces the risk of suffocation and entrapment.

Another worry with a thicker mattress is that it could eventually become a foothold for your little one. With overly thick mattresses there is a higher risk of the baby climbing out of the crib, falling, and getting injured.

To meet the safety requirements set by ASTM, the Cradlewise mattress has been designed to be thin. We’ve ensured that it meets all safety standards while still providing a comfortable sleeping surface for your baby.

Is breathability a factor?

While neither the American Academy of Pediatrics nor the CPCS has outlined any specific requirements for breathability and airflow, you might come across this term in your search for a crib mattress. 

A breathable crib mattress is designed to promote better airflow and keep babies cool. You may also read about breathable mattresses in connection to SIDS prevention.

Although the breathability factor has gained traction in recent years, there is not enough definitive scientific evidence to prove that breathable mattresses help prevent SIDS.

The Cradlewise mattress is made from coconut coir and rubber latex, which are both breathable materials, but it is not a fully breathable mattress. 

The American Academy of Pediatrics recommends that infants should sleep on their backs on a firm and flat surface to reduce the risk of SIDS. Our crib mattress has been designed keeping this in mind.

We are proud to say our mattress passes all ASTM and CPSC safety guidelines to ensure it is safe for your baby.

You also get 100% cotton covers and sheets with your Cradlewise, which can help regulate your baby’s temperature and provide a comfortable sleeping experience. The mesh body of the crib also allows for airflow.

Is GREENGUARD Gold Certification important in a crib mattress?

Indoor air quality is another factor to consider when purchasing a crib mattress. Because babies breathe more air in proportion to their weight compared to adults, minimizing chemical emissions and indoor pollutants may have long-term benefits for infant health.

GREENGUARD Gold certification is a globally recognized standard granted to products that have been tested and proven to have low chemical emissions and promote better indoor air quality. Buying a crib mattress that is certified GREENGUARD Gold is a huge plus. As we said earlier, your baby is going to spend a lot of time in their crib, so it makes sense to want to reduce chemical exposure as much as possible.

The Cradlewise Crib and its mattress are GREENGUARD Gold Certified. 👍

Should a crib mattress be washable, or is a waterproof cover enough?

Not all crib mattresses are designed to be washable. While you can find washable mattresses, many come with crib mattress protectors instead. Other mattresses are made of a water-resistant material that can be wiped down with a damp cloth.

The Cradlewise mattress is not washable because of its natural coconut core, but it can be wiped with a dry cloth to remove dust. 

When you purchase your Cradlewise you get a waterproof mattress cover and a waterproof fitted sheet that are washable. We recommend air-drying the cover and sheets as they may shrink in the dryer. Follow the wash instructions for the best results. 🙌

Save now, sleep (better) later!
Reserve your Cradlewise delivery month early, and save up to $600 on better sleep for the entire family.


  1. Mini crib vs. crib. 2021. Green Active Family. Mini Crib vs Crib: Everything you need to know.
  2. Foam or coil crib. 2021. Green Active Family. Foam or Coil Crib Mattress: How to Decide What’s Best for Your Baby.
  3. Crib mattress features. Happiest Baby. The Best Crib Mattress: What to Look for in a Crib Mattress.
  4. GREENGUARD Gold Certification. 2023. Motherhood Society. GREENGUARD Gold Certified: Why It Matters In Products For Your Baby & Home.
  5. Crib mattress guide. 2016. Consumer Reports. Crib mattress buying guide.
  6. Crib mattress basics. Sealy Baby. Crib mattress basics.
  7. Crib guidelines. Consumer Product Safety Commission. Full-Size Baby Cribs Business Guidance & Small Entity Compliance Guide.

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