What Is A Standard Crib Mattress Size? | Our Guide to Why Dimensions Matter 

 January 7, 2023

By  Jaycen Mag

You're getting ready to design your baby's nursery, but you don't know what the standard crib mattress size is. A lot of new parents agonize over choosing the perfect crib and mattress for their child. But what if you pick one that's too small or too large? Not to mention, a crib is one of the most important pieces of furniture for a baby, and not having the right size mattress can be unsafe for your bundle of joy.

In this article, I will tell you everything you need to know about crib mattress sizes so you can choose the perfect one for your little one.

Key Takeaways

  • Standard cribs are the more traditional option, and they come in various styles to match any nursery decor. Whereas mini cribs are popular due to their smaller size and versatility. 
  • CPSC determined the standard crib mattress dimensions to be 27 1/4 inches x 51 1/4 inches long with a mattress not thicker than six inches!
  • The main types of mattresses available on the market are, innerspring, foam and also organic mattresses.
  • A mattress that is too small can be a safety hazard, as your child could become trapped between the crib bars. 
  • The best way to determine the correct size mattress for your crib is to measure the inside of the crib.
  • Types of Cribs: Standard or Mini Crib

    Is your baby the cutest baby on the block? And as new parents, you want to choose the best for him? Choosing the right crib is one of the most important decisions when setting up a nursery. One key distinction is between standard and mini cribs. Standard cribs are the more traditional option, and they come in various styles to match any nursery decor. Moreover, they typically offer the flexibility to transition to toddler beds.

    Whereas, mini cribs are a newer option on the market, and they are becoming increasingly popular due to their smaller size and versatility. Mini cribs are perfect for small nurseries or for families who travel often. They typically have three sides and a mattress that is about 24 inches x 38 inches. While mini cribs may be more useful if you have smaller nurseries, their small size means they won't last as long. However, they still offer several benefits that may make them worth the investment. Mini crib mattresses are easily available in the market.

    a room for the baby

    For parents who are trying to decide between a standard and mini crib, it is important to consider their individual needs and preferences. While most cribs are rectangular, some come in special shapes like circles and ovals. You will have to get a custom-made shaped crib mattress for them.

    What Is a Standard Crib Mattress Size?

    A standard crib mattress dimensions are 27 1/4 inches x 51 1/4 inches long. These dimensions have been determined by the Consumer Product Safety Commission (CPSC). The CPSC establishes mandatory safety standards for all consumer products, including cribs and mattresses. Moreover, the mattress should not be more than 6 inches thick, providing just enough cushioning for a comfortable night's sleep.

    Types of Crib Mattresses

    There are three main types of crib mattresses available on the market:

    • Innerspring
    • Foam
    • Organic Mattress


    Innerspring crib mattresses are the most popular type. They feature a coil-based support system that allows air to circulate, preventing the baby from becoming uncomfortably hot during the night. However, the first layer is always the insulated pad to ensure a comfortable mattress.

    In addition, an innerspring mattress is more expensive and durable. My husband and I chose innerspring for our baby's bassinet for two reasons: comfort and support. We wanted our little one to sleep soundly and peacefully, and we knew that innerspring would provide the perfect level of firmness.

    Foam Mattresses

    Foam crib mattresses are made from, you guessed it, foam! They provide a firm sleeping surface, support and are equally effective. A foam mattress is usually cheaper than an innerspring. However, changing sheets is more convenient due to it being lightweight.

    Organic Mattress

    Organic crib mattresses are made with natural materials like wool, and cotton. They tend to be more expensive than other types of crib mattresses but offer peace of mind for parents looking for a nontoxic option and are often recommended for babies with allergies or sensitivities. Organic mattress size can be adjusted to suit young babies needs.

    a toy in the crib

    How Do I Know If My Crib Mattress is the Right Size?

    When it comes to crib mattresses, size does matter. A mattress that is too small can be a safety hazard, as your child could potentially become trapped between the bars of the crib. On the other hand, a mattress that is too large could make it difficult for your child to move around and could also be a safety hazard. So how do you know if you have the right size mattress for your crib?

    Here are a few things to keep in mind:

    • The thickness of the mattress should be no more than 6 inches.
    • The length and width of the mattress should be at least 27 inches by 51 inches.
    • The mattress should fit snugly in the crib so that there are no gaps between the edge of the mattress and the side of the crib.
    a crib with toys above it

    Frequently Asked Questions

    Now I will answer the most frequently asked questions about the standard crib mattress size.

    Are There Different Size Crib Mattresses?

    Yes, a wide range of crib mattress sizes is available on the market. Although it is often assumed that all crib mattresses are the same size. The standard size crib mattress is 27 inches by 52 inches, but some mattress companies offer smaller or larger sizes for people who need them. For example, some companies make mini crib mattresses that are 24 inches by 38 inches, which is the size of a mini crib.

    As a result, there is no one-size-fits-all when it comes to crib mattress sizes. Parents should take the time to measure their crib before choosing a mattress so that they can find the perfect fit for baby cribs. Lastly, mini crib mattress size is important because you do not want to put a large mattress in a small crib frame.

    Is a Crib Mattress the Same Size as a Toddler Bed?

    Yes, the toddler bed is usually the same size as the standard crib. The crib mattress dimensions are approximately 28" x 52", while a toddler bed uses a mattress that is around 31" x 56". However, there are slight variations in size between different brands and models. It is important to check the specific dimensions of the mattress before purchasing it to ensure that it will fit properly in the crib or toddler bed. In general, though, a crib mattress can be used for both a crib and a toddler bed.

    What is the Standard Size of a Crib Mattress?

    The standard size for a crib mattress is 51.6 cm x 27.3 cm. When it comes to crib mattresses, size matters. A mini crib mattress that is too small can pose a safety hazard, as there is a risk of the baby becoming trapped between the mattress and the side of the crib. On the other hand, a mattress that is too large can be uncomfortable for the baby and make it difficult for parents to reach in and lift the baby out.

    How To Choose The Right Crib Mattress Size?

    The best way to determine the correct size mattress for your crib is to measure the inside of the crib. Once you have the measurements, you can compare them to the mattress dimensions listed on the product page.

    a crib for a baby

    Final Verdict

    A crib mattress should fit snugly inside the baby crib so that it doesn’t move around. A standard crib mattress size is 52 inches by 28 inches. If you’re in the market for a new crib mattress, these are the dimensions to keep in mind. This size will fit most cribs, but you should always measure your crib to make sure.

    However, you can find mattresses in different sizes and thicknesses, but the standard size is usually best because it’s less likely to slip around inside the crib. Have any questions about crib mattresses or anything else related to baby gear? Leave them in the comments and I will do my best to answer them.

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