Crib Mattress Buying Guide

When you’re getting your baby’s sleep environment together before they’re born, there’s a simple motto that will help you put it together: Bare is best. That means keep it as simple and spare as possible: no stuffed animals, blankets, bumpers, or other items that your baby could roll into. Crib bumpers and blankets can suffocate your baby.

Safety is paramount, so the Consumer Product Safety Commission—which enforces product safety standards, including for baby and kid products—has guidelines to ensure that all standard-sized crib mattresses sold in the U.S. reach a certain safety threshold. That includes sizing—crib mattresses must be no more than 6 inches thick, and must be at least 27¼ inches wide and 51¼ inches long. CPSC guidelines also stipulate that crib mattresses sold with cribs shouldn’t leave more than a ½-inch gap between the mattress and the crib perimeter.

Not all cribs are standard-sized, such as mini cribs or oval cribs. The mattresses that fit those, obviously, will not be standardized, either. Instead, each nonstandard crib should be sold with a mattress that fits it, i.e., it leaves no more than a ½-inch gap between the mattress and the crib perimeter. 

Your baby’s mattress should be firm. It will be much firmer than what seems comfortable to parents. In late 2022, the CPSC instituted new crib mattress safety standards that require a firmness test, because soft mattresses have been linked to infant deaths. You’ll want to make sure that your mattress was manufactured and sold in the U.S. after Aug. 15, 2022, according to the CPSC.

A crib mattress should be firm enough that it doesn’t sink beneath your baby’s weight. That also means no memory foam mattresses, which are designed to soften and conform to your weight. Remember: Keep it simple!

One thing you’ll discover when you have your baby is that they tend to be messy. Diapers leak and babies spit up, which can make the mattress damp and grimy, and potentially lead to the growth of mildew and mold. You’ll want to buy a separate mattress cover to protect the mattress from microbes that can endanger your baby. 

Babies shouldn’t sleep in your bed, either. The American Academy of Pediatrics (AAP) recommends against bed-sharing of any kind, including putting siblings in the same crib or sleeping with the baby in your own bed. Adult beds come with many adult accouterments—blankets, pillows—that baby doesn’t need and that could actually be risky. Soft bedding and loose items can increase your baby’s risk of suffocation and strangulation. If you fall asleep with your baby in your bed, place them in their own crib when you wake up. 

There are two primary types of crib mattresses: foam and innerspring. “Whether one is better than the other is really based on parent priorities,” says Carolynne Harvey, an infant and toddler sleep expert. “You can find good options in each category.” If you’re using your crib mattress with your next baby, make sure it’s still firm enough not to indent beneath your baby’s head or change shape when you put a fitted sheet on it. If it does, you’ll want to buy a new one.

Foam mattresses are usually made from high-density polyurethane foam. At about 8 to 13 pounds, foam mattresses tend to be lighter than innerspring mattresses, which makes them easier to maneuver when changing the sheets or the crib mattress height. They tend to be less expensive than innerspring mattresses, ranging from about $40 to $400, but they can wear out more quickly, too—if the mattress begins to get softer and compress beneath the weight of your baby, it’s time to get a new one. 

This type of foam is different from memory foam, which is also known as “viscoelastic foam” and is designed to slowly conform to a shape that’s placed on it. (Remember, you don’t want your baby’s mattress to change shape when they’re placed on it! The mattress should remain firm.)

Innerspring crib mattresses contain steel coils that are surrounded by cotton or foam cushioning. They typically cost between $60 and $1,300 or more. They’re heavier, weighing between 10 and 20 pounds, and tend to be more durable than foam mattresses. “Innerspring mattresses still outsell foam crib mattresses as their construction usually leads to a longer life,” says Jenny Son, vice president and general merchandising manager at Buybuy Baby.

You can judge the firmness and quality of an innerspring mattress by its coil count. Coils, aka springs, are made of steel and form the primary support in an innerspring mattress. They generally number from 80 to more than 200 coils per crib mattress. More coils, more support. This is important because babies need super firm, supportive mattresses—remember, it doesn’t need to be a mattress that you would find comfortable.

Steel gauge is another metric by which you can judge the firmness of a crib mattress. Steel gauge refers to the thickness of the coil springs. Lower numbers equal thicker gauge; a thicker steel gauge makes for a firmer mattress. Some nicer innerspring mattresses also have border rods, which are steel bars around the edges of the mattress for extra firmness around the edges.

Firmness and sizing are the two most important things to consider when making your purchase. The mattress shouldn’t indent when your baby lies on it, according to the AAP. And the mattress should fit nice and snugly into the crib, with no gaps. 

Hybrid mattresses are two-sided mattresses that can be used from the early days through toddlerhood. They’re also called two-stage, dual firm, or convertible crib mattresses. The infant side is firm, while the toddler side is a bit softer; however, according to the CPSC, both sides must be firm enough to be safe for a newborn; these mattresses typically come with guidance on when to flip them.

Messy babies can make for a messy crib mattress, which is why you’re going to need some kind of waterproof crib mattress cover. Diaper leaks and blowouts, spit-up, and any other liquid spill can make your baby’s mattress gross—and dangerous. Babies’ immune systems are particularly susceptible to harmful mold, bacteria, and other germs in their crib mattress, so you’ll definitely want to keep that thing clean. The best way to do that is by buying a washable, and perhaps waterproof, mattress cover. “I definitely recommend buying a separate waterproof cover,” Harvey says—and they’re safe.

The AAP recommends a flannel-backed, waterproof mattress cover, which will be comfortable and cooler for baby. Make sure the cover fits perfectly over the mattress, which should remain firm. Vinyl covers are popular and effective, but you may want to consider getting a mattress cover that is free of PVC (polyvinyl chloride), according to James Dickerson, PhD, chief scientific officer and science adviser to the CEO at Consumer Reports. Vinyl is likely to have remnant phthalates in it, which aren’t safe for baby’s development. According to the CPSC, phthalates can be harmful in particular for males’ reproductive development. “Look for products that say explicitly vinyl-free or phthalate-free,” Dickerson says. PVC-free, phthalate-free, and vinyl-free crib mattress covers aren’t hard to find; companies will often advertise these attributes on their packaging or online.

“It’s possible to go the all-fabric route, too,” Dickerson says. “You’re just going to have a lot of thin layers, rather than one thick layer.” Provided that you have enough of a barrier between the mattress and the baby, so that stains don’t reach the mattress itself, you’re good.

Some baby gear companies now market what they call “breathable” mattresses, which they say promote safe sleep, reduce the chances of suffocation or overheating, and prevent “rebreathing”—when a baby breathes in their own carbon dioxide, which has been hypothesized to contribute to SIDS (sudden infant death syndrome).

However, according to the AAP, there’s no evidence that rebreathing definitively leads to SIDS, nor is there epidemiological evidence that “breathable” mattresses can protect from SIDS. That said, there’s no real reason not to buy one of these mattresses, provided that they’re firm and fit snugly into the crib. You’ll also, again, want to make sure that you’re using a waterproof mattress cover so that your crib mattress doesn’t accumulate mold, mildew, and other microbes, which are harmful to your baby. 

The Department of Agriculture regulates the term “organic,” and if a mattress has an “organic” seal, it should be made of at least 95 percent organic material. However, the CPSC does not regulate the term, so there are no guidelines as it pertains to crib mattresses specifically separate from the overall USDA regulations. 

You can rest assured that crib mattresses are required to pass certain safety standards, including phthalate and lead content limits. If you want extra safety certifications, though, you can look for one of these.

Greenguard Gold sets limits on and tests for chemical emissions.

CertiPUR-US sets standards and tests for formaldehyde, heavy metals, and volatile organic compound emissions.

Global Organic Textile Standard (GOTS) label grade “organic” requires that at least 95 percent of a crib mattress’s materials are certified organic. It also prohibits certain compounds like phthalates and chemical flame retardants.

Global Organic Latex Standard (GOLS) guarantees that crib mattresses are made with 95 percent latex rubber sap content from rubber tree plantations that are certified organic.

First things first: Get that waterproof mattress cover! It’ll make cleanup so much easier. You can wipe the waterproof cover with a damp cloth or sponge and soapy water and let it dry before putting clean sheets back on. Don’t use harsh cleaning products or bleach, which might be bad for the waterproof layer.

Some mattress covers allow machine washing, then tumble drying on low. Wash it as needed—in other words, when your baby has any kind of accident. You can use whichever laundry detergent you typically like. But if your baby shows signs of skin allergies, or you simply feel like making the switch to something gentler, know that Consumer Reports gives Kirkland Signature Ultra Clean Free & Clear detergent a very good rating. 

Ideally, your crib mattress cover is good enough that you won’t need to clean the mattress itself. If a stain happens to get through to the mattress, soak up any liquid with a dry rag, spot clean the mattress with soap and water, then let it dry before putting the mattress cover and sheets back on. Check the product instructions, though, for guidance on your specific crib mattress.