How To Choose The Right Crib Mattress Size: The Complete Parents’ Guide

With a baby on the way, you are likely going to spend a significant amount of time designing a nursery, which requires making decisions about everything from paint colors to diaper storage. In addition to these design choices, you’ll also have some decisions to make about the place where your little one will spend most of their time — the crib.

Choosing a crib and the correct crib mattress size are major decisions not only for the design of your nursery but also for your baby’s safety. In this article, the experts at Newton Baby discuss the types of cribs and their corresponding crib mattress sizes so that you can make an informed decision for your new little one.

Crib Types: Advantages And Disadvantages

The color and style of the crib you choose for your baby’s nursery are important, but size is another critical factor to consider. Here are a few guidelines to keep in mind when making your decision about which type of crib to purchase.

Standard Cribs

Dad changing his baby in front of a crib

A standard-sized crib is the typical go-to for most parents. Measuring around 28 inches by 52 inches, standard cribs are significantly larger than mini cribs.

While a standard (or regular) crib is often more expensive than a mini crib, the biggest advantage of a regular crib is that your child will get several years of use out of their baby bed.

Many standard cribs can be converted into toddler beds, so you won’t need to buy a new bed once your child discovers how to escape from their crib. But if you decide to switch things up and buy your little one a fun toddler bed, you can purchase a toddler bed frame and use the same standard crib mattress.

Mini Cribs

White mini crib in a nursery

You can probably guess the advantages of a mini crib just from its name. At 24 inches wide and 38 inches long, the mini crib is smaller than a standard-sized crib. This small size is especially useful if your nursery is short on space.

Additionally, mini cribs are ideal if your new baby will be sharing a bedroom with their older sibling or if you’re putting two cribs in the same nursery for twins. You can also purchase a mini crib to leave at grandma and grandpa’s house to make overnight stays more convenient.

If you need a portable crib that can easily roll around the nursery, choose a mini crib with wheels. Just be sure the wheels are locked and the crib is securely in place when you’re not moving it.

Finally, compared to standard cribs, mini cribs are easier on your wallet. But before you make your decision based on that fact alone, remember that your baby will outgrow their mini crib — usually around two years old or, sometimes, earlier. At that point, you’ll need to buy a bigger bed to fit your growing toddler.

Shaped Cribs

Baby standing up in his white shaped crib

As with all baby items, there’s no shortage of adorable touches and unique additions when it comes to cribs. While standard and mini cribs are rectangular, some cribs are available in special shapes — like circles or ovals — and have mattresses to match.

These cribs are a good option if you want to add a unique design element to your baby’s nursery. Shaped cribs are often smaller than standard ones, though, so keep that in mind while you’re crib shopping.

Choosing The Right Crib Mattress Size

Example of a standard crib mattress size

Once you have picked out the best crib for your baby, all that’s left to do is to choose the right mattress. While this may seem easy, there are a few things to consider as you shop. The first thing to know is the difference between mattress sizes.

When it comes to crib mattress sizes and the safety of your baby, you want to be sure that the mattress fits inside the crib snugly with as little space as possible between the two. A large gap can pose a safety risk for your baby.

As a rule, when the mattress is inside the crib, you should not be able to fit more than two fingers between it and the crib frame. But let’s talk more specifically about each crib mattress size.

Crib Mattress Size: Standard

Standard crib mattress size dimensions

Dimensions

As you might guess from the name, the standard crib mattress is the typical mattress size for baby cribs.

According to the Consumer Products Safety Commission, a standard (or regular) crib mattress should be no more than 6 inches thick and measure at least 27 1/4 inches wide and 51 1/4 inches long.

Tips For Selecting The Right Standard Crib Mattress

If you have a standard-sized crib for your little one to snooze in, you’ll need a standard-sized crib mattress.

As we mentioned, the size of these mattresses is regulated. However, there is a bit of wiggle room within the regulated size of a crib. A standard crib can be ⅝ of an inch larger or smaller than the regulated 28 by 52 ⅜ rectangle.

A standard mattress will typically fit a standard crib, but because of this small variation, you will still need to check to make sure your mattress fits properly — not too big and not too small.

Here’s an example: if your crib is on the large side of the regulated measurements and your mattress is on the small side, you may end up with a gap in-between the mattress and the crib. Always check the fit before putting your baby in bed for the first time.

Crib Mattress Size: Mini

Mini crib mattress size example

Dimensions

Coming in smaller than the standard crib mattress is the mini crib mattress. The government does not regulate the size of mini crib mattresses as they do for standard ones. However, the typical size is 24 inches wide and 38 inches long.

Tips For Selecting The Right Mini Crib Mattress

While you can likely purchase most mini crib mattresses and expect them to fit your mini crib, you’ll still want to double-check the fit because some mini cribs are narrower than others. Mini crib mattresses are also available in different depths, so be sure to research the dimensions before making a decision.

Crib Mattress Size: Shaped

Dimensions

There are no standard specifications or government regulations for shaped crib mattresses. Shaped cribs vary in size and most will likely come with a mattress.

Tips For Selecting The Right Shaped Mattress

If you have a specially shaped crib, the same rule applies for the mattress: not too big and not too small.

If your shaped crib does not come with a mattress, you’ll want to use a tape measure to determine the appropriate size and then choose a mattress that fits snugly inside your crib without too much room around the edges.

Additional Tips For Choosing A Crib Mattress

woman holding her sleeping baby

As you begin to explore the world of crib mattresses, you’ll realize that size is not the only factor that differentiates one mattress from another. You’ll need to keep a few other factors in mind.

Firmness

First of all, crib mattresses should be firm. While your older child might appreciate a soft and cozy bed, when it comes to your infant, the firmer the mattress the better. Soft mattresses can increase the safety risks for young babies.

It’s important to note, however, that “firm” does not necessarily mean hard. Traditional crib mattresses are rock-hard because, in order to prevent a baby's head from sinking in and to avoid suffocation risk, they are encased in non-breathable plastic.

By making the Newton mattress completely breathable, we were able to make it much more comfortable as well — without any risk of suffocation.

To be sure you have a firm crib mattress, push down on it and see if it immediately springs back into place when you take your hand away.

Breathability

Secondly, consider going with a breathable crib mattress. This is important because non-breathable mattresses may increase the risk of suffocation for young babies.

However, you can put yourself at ease with a breathable mattress, like Newton Baby’s Crib Mattress, which allows air to flow freely for optimal breathability and temperature regulation while your little one sleeps.



Newton Baby’s Crib Mattress is made with patented Wovenaire® technology and zipped into a comfortable, washable, and breathable mattress cover.

In fact, you can get the most out of your breathable mattress by using Newton Baby’s Waterproof Crib Mattress Pad and skipping the sheet. The mattress pad is durable, comfortable for your little one, and machine-washable. It’s as easy as that!

As you prepare for your baby’s arrival, check one thing off your list and put your mind at ease by choosing a Newton Baby Crib Mattress designed with your baby’s health, safety, and comfort in mind. Every mattress made by Newton Baby is 100% breathable, 100% washable, and 100% recyclable.

Smiling baby on a Newton Baby crib mattress

With a little knowledge and the tips we’ve listed here, you can have a pretty, functional crib and crib mattress that are comfortable enough for baby to rest well and safe enough to put your mind at ease.

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