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What Size Is a Crib Mattress? A Complete Guide

From the Puffy Editorial Team | 2 min read.
What Size Is a Crib Mattress? A Complete Guide

As a new parent, choosing the right size crib mattress can be overwhelming. With so many options and sizes available, it can be hard to know which one is right for your baby's crib. In this article, we'll take a closer look at crib mattress sizes, including the standard size, mini size, and mattress sizes for convertible cribs. By the end, you'll have a better understanding of which crib mattress size is right for you and your little one.

What is a Crib Mattress?

A crib mattress is a specially designed mattress made for infants and young children to sleep on. Crib mattresses are firmer than regular mattresses and meet strict safety standards to reduce the risk of Sudden Infant Death Syndrome (SIDS). Crib mattresses are typically made from foam or innerspring materials, and some also feature waterproof covers to protect against spills and accidents.

What Size is a Crib Mattress?

The standard size for a crib mattress is 28 inches by 52 inches. This size fits most standard cribs and is the size recommended by the Consumer Product Safety Commission (CPSC). The thickness of a standard crib mattress should be no more than 6 inches to ensure a safe fit in the crib.

What is the Size of a Standard Crib Mattress?

As mentioned, the standard size for a crib mattress is 28 inches by 52 inches. This size is recommended by the CPSC and is designed to fit most standard cribs. It's important to measure the interior of your crib before purchasing a mattress to ensure a snug and safe fit. Additionally, it's recommended to use a tightly fitted sheet and avoid any loose bedding or toys in the crib to reduce the risk of suffocation or SIDS.

What Size Mattress for Convertible Crib Mattress?

A convertible crib is a crib that can be converted into a toddler bed, daybed, or even a full-size bed as your child grows. The size of the mattress needed for a convertible crib will depend on the specific conversion kit used. Some conversion kits will require a standard size crib mattress, while others may require a larger size. It's important to consult the manufacturer's instructions and guidelines before purchasing a mattress for a convertible crib to ensure the correct size is used.

What Size is a Mini Crib Mattress?

A mini crib is a smaller, more compact crib designed for small spaces or travel. The size of a mini crib mattress is typically 24 inches by 38 inches, making it smaller than a standard crib mattress. It's important to note that mini cribs are not designed to be used long-term and are typically only suitable for infants up to six months old.


Choosing the right size crib mattress is an important decision for parents. By understanding the different crib mattress sizes, you can make an informed decision about which size is best for your baby's crib. Whether you opt for a standard size crib mattress, a mini crib mattress, or a mattress for a convertible crib, ensuring a snug and safe fit is key to creating a safe sleep environment for your little one.

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