Foam core mattresses are more popular these days, but a traditional innerspring crib mattress is firm and durable. In this category, Sealy Baby's FlexCool crib mattress shines with its 204 coils and anti-sag steel bars for support. A higher coil count translates to a firmer mattress, as there are fewer gaps between each coil. Innerspring mattresses tend to sleep cooler because air can flow freely between the springs. 

The FlexCool is a two-stage crib mattress with an extra firm side for infants and a softer side for toddlers. The mattress is Greenguard Gold certified, which means it's tested to ensure its materials don't emit any chemicals that could affect the air your child breathes. One downside of innerspring crib mattresses is that they're heavier than their foam core counterparts. The FlexCool weighs shy of 15 pounds. That might not sound like a lot, but the extra weight could make changing sheets even more of a chore.

With the rise of brands such as Casper and Purple, the mattress in a box has carved out a niche in the mattress space. It should come as no surprise then that the mattress in a box model has made its way into the crib mattress category. The Graco Deluxe Foam Crib and Toddler Mattress is a standard mattress that's compressed, rolled up and crammed in a space-efficient box for easy shipping. Like other mattresses packaged this way, the Graco self-expands once it's removed from the box. Once fully expanded, the mattress is ready to be placed in your crib. However, some owners report that the mattress never fully expands to its correct 4-inch thickness. You should contact the retailer and ask for a replacement if this happens with yours.

The Graco Deluxe is Greenguard Gold certified and comes with a removable water-resistant cover that's machine-washable, something you'll appreciate at 3 a.m. when your little one wakes up from a soaked, leaky diaper. Though the mattress is suitable for both babies and toddlers, it has the same level of firmness on both sides.

If you have budget to spare, the waterproof crib mattress from Newton Baby is an excellent option. Newton prides itself on its use of breathable materials and construction, and its crib mattresses show off the company's innovations best. Newton's proprietary Wovenaire core is made of food-grade polymer mesh, which is 90% air by volume. This allows air to flow freely through the mattress, reducing the risk of suffocation. As a bonus, it also allows you to hose down the mattress if it gets super-gross. You need to set aside two to six hours to let it dry. The cover is also washable and waterproof. Hopefully, that would catch all the grossness before it hits the mattress, but it's nice to have options just in case. 

The Newton is a dual-stage crib mattress with a fully breathable side for babies and a waterproof side for toddlers who are potty training. The mattress is not organic, though the company says the materials are all hypoallergenic. It's also Greenguard Gold certified, which is good if you're a parent who plans to put the breathability claim to the test as soon as you get it out of the package (I see you, curious dads). Though it's undoubtedly pricey, the Newton could give you extra peace of mind.

The Newton boasts some impressive tech, but it's not the only breathable crib mattress in town. Halo, a safe sleep pioneer, known for its sleep sacks and swiveling bassinet, has a breathable crib mattress that's worth a look. Called the DreamWeave after its breathable mesh core, the mattress is made up of food-grade polymers, but it's mostly just pockets of air. The mattress cover is also breathable and has two sides -- a 3D mesh quilted side for infants and a toddler side that's waterproof to protect against accidents. Should some leakage get through the cover, the mattress itself can be rinsed off like the Newton.  

The Halo Dreamwave is Greenguard Gold certified and uses hypoallergenic materials. Though this mattress is still expensive, it's cheaper than the Newton and offers similar features.   

If you want your baby to sleep on a crib mattress made of organic, natural materials, you'll like the options from Naturepedic. Their mattresses use a food-grade polyurethane "WaveSupport" core and organic cotton for filling. Meanwhile, the waterproof cover is made of non-GMO sugarcane and wipes clean easily. The mattress is GOTS certified for organic and sustainably sourced materials and Greenguard Gold certified.

This particular crib mattress has the same firmness on both sides, but Naturepedic makes a two-stage version. If your baby has sensitive skin and you like the ecological benefits of going organic, an organic crib mattress might make sense for you. 

Changing crib sheets is hard enough, thanks to the necessary extra-snug fit of the mattress, so we get it if you want to make the process easier on yourself with a lighter mattress. The Lullaby Earth Super Lightweight Mattress is waterproof, Greenguard Gold certified and weighs just 7 pounds. That's a good deal lighter than most foam core mattresses, weighing as much as 15 pounds. 

The Lullaby Earth features a waterproof cover that wipes clean with soap and water. The core and cover are made of food-grade polymers, which the company says increases the mattress's recyclability. A two-stage version with dual firmness levels is also available, costing a little more money but not more weight. 

Not everyone has several hundred dollars to throw at a crib mattress. That's why it's nice to know there are still good options at the lower end of the pricing spectrum. Safety 1st is well known in the industry for its competitively priced baby products, and the brand's focus on affordability and value naturally carries over to its crib mattress offerings. The Safety 1st Heavenly Dreams crib mattress is a sub-$100 option that offers a surprising amount of features for the money. Its core is made of high-density thermo-bonded polyester fiber, while the waterproof cover is vinyl. It's also lightweight, weighing just 7.5 pounds. 

You might not think you can get Greenguard Gold certification at the under-$100 price point, but Heavenly Dreams delivers that coveted green seal of approval. The two-stage version of Heavenly Dreams is currently unavailable, but at this price you could buy the toddler version when you're ready to upgrade and still spend less than you would on many two-stage mattresses on the market. If you don't need ultra-premium features or organic materials, the Safety 1st is a solid bet. 

There are many reasons to go with a mini crib over a full-size crib. They're compact and have a much smaller footprint than their full-size counterparts, which means you'll have an easier time fitting one in your room. Some mini cribs even fold and have legs with lockable caster wheels, further increasing their flexibility. If you decide a mini crib is the right fit for your baby and living space, then you're going to need a crib mattress to go with it. 

Though full-size cribs must accommodate a standard mattress size, there's no such regulation for mini cribs. Manufacturers tend to stick to a certain size (24 by 38 inches), but it's still important to measure your mini crib to ensure you'll have a close fit. If your mini crib is a common size, the Dream on Me Portable Mattress is a stand-out choice. It's Greenguard Gold certified, has a waterproof cover and is exceptionally lightweight at just 2.5 pounds. On top of all that, it's very affordable at under $50. 

What are the different types of crib mattresses?

There are several ways you can break down the types of crib mattresses available, but generally, they fall into two categories:

Innerspring mattress: An innerspring crib mattress is a more traditional mattress that relies on internal coil springs for support. The higher the number of coils, the more supportive the mattress. As a result of having hundreds of steel coils for a core, innerspring mattresses are almost always heavier than their foam counterparts. They also tend to be pricier.

Foam mattress: Foam crib mattresses make up the vast majority of the market. They're typically made of polyurethane foam and can be relatively inexpensive due to their simpler construction than innerspring mattresses. Within the foam crib mattress category, you have breathable mattresses, which feature woven polymer cores that allow air to pass through them more easily. 

Do babies like a firm mattress?

You might like the pillowy, sink-in feel of a soft mattress, but your baby needs to sleep on something a good deal firmer for their safety. According to Alex Savy, a certified sleep science coach and founder of SleepingOcean, a good crib mattress must be firm and supportive as a precaution against SIDS. The American Academy of Pediatrics says soft mattresses, including those made of memory foam, can form indentations that increase suffocation risk.  

"A crib mattress should not be cushioning and hugging," says Savy. "Instead, it must spring back quicklywhen the pressure is applied."

What does Greenguard Gold certified mean?

You'll often see this certification on crib mattresses and many other baby products. Greenguard Gold certification signifies that a product has passed a battery of tests looking for chemical emissions called Volatile Organic Compounds. These pollutants are released as a gas from paints, cleaning supplies and materials. A Greenguard Gold certified product has proven itself to emit a very low amount of VOCs, if any. 

Though Greenguard Gold is the most prevalent among crib mattresses, you'll see numerous other awards and certifications. CertiPur-US is similar in that it certifies a product has low VOCs, but a mattress with this certification has also been made without ozone depleters, toxic flame retardants or phthalates. However, Greenguard Gold is generally considered to be the more stringent standard.   

Do all crib mattresses fit all cribs?

All standard-size crib mattresses are required by law to measure between 51 and 5/8 to 53 inches long and 27 and 1/4 to 28 inches wide. So yes, in theory, any crib mattress on sale today should fit any crib, but some will fit better than others. Some mattresses' corners are square, while others are rounded, leaving gaps. According to the Consumer Product Safety Commission, you should have no gaps larger than two fingers between the mattress and the crib's sides.