How to Choose a Crib Mattress: Tips on Fit and Precautions

Updated August 30, 2021
Overhead portrait of baby boy in crib at home

When preparing the nursery for a little one's arrival, there is so much to consider, including purchasing a crib mattress. Spend some time learning how to choose a crib mattress, because where you place your most precious gift to sleep is not to be taken lightly.

Types of Crib Mattresses

When you begin searching for the best crib mattress, you'll discover that there are several options available. You'll need to take several features into account, just as if you were shopping for a mattress for your own bed. There are two main types of mattresses for a crib: innerspring and foam.

Innerspring Mattress

An innerspring mattress is typically more expensive than a foam mattress. However, they may also hold up longer. The number of coils in the mattress you choose will significantly impact how well the mattress is made. It is best to purchase a mattress with at least 150 coils, and the covering of the mattress should be thick.

Foam Mattress

Foam mattresses don't have inner springs or coils. Their firmness is dependant upon the density of the foam. If choosing a foam mattress, go with a mattress that appears supportive, firm, and solid. This doesn't necessarily mean thicker, however. Foam mattresses of lesser density will not hold their shape for as long, and you may need to replace a foam mattress before your child has outgrown their baby bed. Today, many foam mattresses are as well-constructed as innerspring mattresses; however, many parents prefer them because they are much lighter in weight, making them much easier to maneuver. Remember to pay close attention to the density of a foam mattress if this is the type of mattress you want to purchase.

Non-Toxic Crib Mattresses

Many crib mattresses emit toxic chemicals over time. Often referred to as volatile organic compounds (VOCs), mattresses release chemicals into the air through a process called off-gassing. What is even more startling is that these chemicals are more readily released with the addition of heat (including body heat from your tiny baby) and are strongest in the infant's immediate breathing zone. The materials most commonly associated with toxicity are:

  • Polyurethane Foam - Often used in crib filler materials
  • Flame-Retardant Chemicals

  • Vinyl (PVC) - Often used in waterproofing mattresses

If avoiding toxins at all costs is at the top of your parental concern list, choose a crib mattress with a Greenguard Gold Certification. Products with this certification have been tested for chemical emissions. One of two levels is assigned to products, like crib mattresses, that have been linked to low toxin emissions:

  • Greenguard Certification
  • Greenguard Gold Certification

Organic Doesn't Mean Non-Toxic

A common misconception regarding organic crib mattresses is that they equate to being non-toxic. This isn't particularly true, and many certified organic mattresses can still contain materials associated with high levels of toxins. If a mattress says it was "made with organic" materials, there is plenty of room for interpretation. Was it made with 1% of organic materials, or was it made with 99% of organic materials?

Find the Perfect Fit

How important is the fit of your baby's crib mattress? This is a critical issue! The mattress should fit snuggly into the baby bed, be the correct size and be firm enough to ensure infant safety.

African Baby sleeping in crib

Crib Mattress Measurements

The standard measurement of a basic baby bed is 51 5/8" by 27 1/4". With a standard crib, you will want to be sure to purchase a standard crib mattress. Use the two-finger check when you install your mattress into the crib. If you feel a space of more than two fingers between the mattress and the crib frame, the mattress doesn't fit properly, and your baby could be at risk for entrapment and suffocation. Cribs also come in a mini-crib size, measuring 24 by 38 inches. If you are planning to put your baby in a mini crib, purchase the correlating mini mattress.

Crib Mattress Thickness and Firmness

All parents want their babies cozy and comfy when they nod off to slumberland, but nestling into soft bedding is not the safest option for an infant. When it comes to the crib mattress, firmer is better. The mattress doesn't have to be rock hard, but it does have to be firm, so that infant breathing doesn't become restricted. Soft mattresses pose dangers to babies, especially regarding suffocation and SIDS dangers.

The thickness of a crib mattress can vary, depending on whether the mattress is innerspring-based or made of foam. Generally speaking, spring mattresses are thicker than foam ones. A good rule of thumb is to choose a crib mattress that is no more than six inches thick. Never place a foam topper on an infant mattress. While foam mattresses themselves are acceptable, foam toppers placed on top of mattresses are not.

Baby in crib surrounded by toys

What Goes on the Mattress Matters

Once you have purchased your crib and correlating mattress, you'll need to look at what goes on your mattress. Mattress covers are popular options for parents looking to protect their baby's mattress, and mattress sheets have unique qualities and features that parents will want to pay particular attention to.

Mattress Protector

You can actually purchase crib mattresses that have a vinyl, waterproof cover. These are great, as your baby's diapers won't always be leakproof. If your baby is still using their crib once you begin potty training, you'll be glad that the cover on the crib mattress is waterproof, too! Aside from waterproof material, consider a mattress cover that is:

  • Hypoallergenic - Aids in keeping allergens away from your baby's face and body
  • Breathable - Creates a cooler and more comfortable arena for your sleeping baby

Make sure the crib mattress protector fits snugly over the crib mattress and doesn't add any plushness, lumps, bumps, or pockets to the space. It should have the ability to be easily removed from the crib mattress and washed in the event of soiling.

Mattress Sheets

Many parents choose crib sheets based on specific design elements, wanting the sheets to correlate to the rest of the nursery decor. It's far more important to choose a crib sheet for its functionality.

  • Fitted sheets are always best. You want the sheet to stay snug atop the mattress, so no material gets loose and impedes baby's breathing.
  • Cotton sheets- Cotton sheets are typically soft, breathable, and made of natural material, all of which are appealing qualities to parents. Note that cotton shrinks, so after a first wash, the sheets might seem tighter than usual.
  • Linen sheets- Linen is a popular material for crib sheets because of its natural fibers, breathability, resistance to dirt, hypoallergenic qualities, and durability. Like cotton sheets, linen sheets can shrink and feel rough to the skin's surface.
  • Bamboo sheets - Bamboo sheets are soft to the touch and absorb moisture well. Chemicals may be used in the process of producing bamboo sheets, putting some parents off.
  • Organic Sheets - Organic sheets often cost more than non-organic sheets; but they are made without the heavy pesticides that are often included in materials like cotton.

Crib Mattress Pricing

Like many baby items, crib mattresses range in price. Parents can expect to pay anywhere from $30 to thousands of dollars for their baby's mattress. The price depends on the quality of materials used to make the mattress, and the brand of the mattress. Rest assured that there is a quality mattress out there for your little one, no matter what your budget is.

Take Your Time and Do Your Research

When it comes time to plunk down money on a crib mattress, do so knowing you chose the very best option for your child. Consider what is important to you personally. Look at the varying materials and price points and pick a crib mattress that brings you peace of mind.

How to Choose a Crib Mattress: Tips on Fit and Precautions