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Crib Mattress Size Guide

Fact Checked
Up to date
Update: April 28, 2023
7 min read

Written by

kritika joshi
Content Writer
Illustration Of Crib Mattress Sizes

“Angels wait for babies to close their eyes so that they can sing them a lullaby”- Unknown.

Babies won’t make angels wait if they get a safe and comfortable sleeping environment. A spacious crib with narrow slats and a snugly fitting mattress that is breathable, firm, and non-toxic will make the apple of your eyes enjoy a healthy sleep. A crib mattress size matters for ensuring your baby’s comfort. In this article, we will learn about your newborn’s crib types and mattress size.

Crib Mattress Size Chart

Standard Crib Mattress SizeMini Crib mattress SizeShaped Crib Mattress Size
Dimensions In Inches27in X 51in24in X 38inShaped crib mattress sizes have no standard specifications or don’t have any government regulations
Dimensions In Centimetres68.58cm X 129.54cm60.96cm X 96.52cm

The standard and mini-size crib mattress sizes have specific regulations prescribed by the Consumer Product Safety Commission. Shaped-size cribs and mattresses have no such restrictions. The regulations are to prevent mishaps from suffocation leading to sudden infant death syndrome and the head entrapment of an infant between the mattress and the crib sides. Ensure a ½-inch gap between the bed and the crib side for the child’s safety. Below is the crib mattress size chart of the different crib mattress dimensions.

Types of Cribs

Cribs are available in various sizes, such as a standard crib, mini crib, and the shaped crib where the shape can be oval, circular, or hexagonal. The choice of cribs will depend on your room space, the crib size and its usability. Moreover, the crib slats should be close enough to prevent the baby’s head from getting stuck.

Standard Cribs    

Standard cribs are popular among many parents due to several reasons. The traditional crib can be used for longer and comes in a rectangular size with dimensions of 28 inches in width and 51 inches in length. Standard cribs ensure your child has enough space to roll around while changing the side or moving around. 

The crib measurements are considered per the crib mattress regulation guidelines to ensure your child’s safety. A standard crib can also be converted into a perfect size for a toddler bed. Thus, you won’t need to invest in another bed in the near future. However, it is expensive compared to a mini crib. Due to the specific guidelines, choosing a crib and mattress becomes easy.

Mini Cribs

Compared to standard cribs, mini cribs are smaller and suitable for small spaces. The dimensions are 24 inches in width and 38 inches in length. Many mini cribs come with wheels ideal for travelling. The protection cover hook protects your infant from insects and mosquitoes during outings. Moreover, while you are busy with your guests in the living room, keeping a watch over your infant is easy due to its portability. Ensure the wheels are locked when the baby is sleeping. 

Many people only buy a mini crib as an additional crib to use while travelling. Being foldable, they can be easily adjusted in a car. Mini cribs are less expensive than standard cribs and can’t be used longer as the infant can outgrow the crib in 1.5 months to 18 months. If you want to provide a different bed when your baby becomes a toddler, then a mini crib is the ideal preference. 

Shaped Cribs 

The shaped cribs can be in a circle or oval shape. They are unique and have aesthetic touch. However, shaped cribs are comparatively smaller than standard and mini cribs. But they do come with mattresses with no specific regulations regarding the size. In a round-shaped crib, the babies can see all around, and you can easily view your sleeping baby from all sides. 

Moreover, due to the ideal height of the crib, putting and lifting your baby is easy. The shaped crib is without corners, hence is a safe option. It can’t be carried easily from one room to another. You have to reassemble the crib if the need arises.

 Due to the small space, infants can’t move around comfortably. Further, the cribs are not convertible as standard cribs. Due to various shapes, mattress options are limited. Shaped cribs are ideal for the short term and a contemporary look.

How to Choose the Right Crib Mattress Size?

Cribs come in various shapes and sizes. Thus it might be overwhelming, and you might keep guessing what size is a crib mattress. 

The mattress size is most important for your infant’s comfortable sleep. Measure the inner parameters of the crib while purchasing a cushion to confirm there is no gap of more than two fingers between the mattress and the crib side.

 Below are the guidelines for the dimensions of a crib mattress while choosing the right crib mattress size for different crib styles. 

Standard Crib Mattress Size 

According to the Consumer Products Safety Commission [CPSC], the full-size crib mattress shouldn’t be more than 6 inches thick. The dimensions of a standard-sized crib mattress should be at least 27 ¼ inches wide and 51 ¼ inches long. There should be some space left between the bed and the crib. The standard crib size can be ⅝ of an inch large or small if you prefer the tape measurement for an accurate reading. Ensure the mattress is neither too big nor small for the crib. Moreover, read the manufacturer’s guidelines before purchasing the mattress. 

Mini Crib Mattress Size

Mini cribs are best conformed for small spaces and are considered a lifestyle choice. It is best while sharing rooms or for twins. The mini crib mattress size must be 24 inches wide and 38 inches long. As some mini cribs are narrower than others, you should ensure the dimensions of the mini crib and the mattress. The perfect measurements will help you choose the mattress that goes well with the crib, and your child will be safe from unwanted accidents. 

Shaped Crib Mattress Size

Shaped cribs are available in various sizes. Most shaped cribs come with a mattress. However, you should still double-check the size for your child’s safety. Similar to standard and mini-size cribs, the shaped mattress shouldn’t be too long or small for the crib. If the crib doesn’t come with a mattress that fits well, do measurements of the crib and the mattress with tape while purchasing. The appropriate size that fits snugly inside the crib matters the most. There shouldn’t be any space left around the edges of the mattress. 

Twin vs Crib Mattress Size

In comparison between twin mattress vs crib mattress size, the twin mattress is slightly larger than a crib mattress with a measurement of 38 inches x 75 inches. It’s convenient to use when the infant turns into a toddler gradually.

Toddler Mattress Size

The approximate measurement of a toddler mattress size is 27 inches wide and 52 inches long. Though it fits a toddler bed, it is best to ensure no void between the mattress and the crib frame for your baby’s convenience.

How to Choose a Crib Mattress

While choosing a crib mattress, ensure the mattress tightly fits in the crib, is washable, and waterproof. Many hyper-allergic, dust, and mites resistance mattresses are available per the regulated guidelines. 

Before buying any mattress, press the bed at the centre and edges. If it snaps back readily and doesn’t take the shape of the hand, the mattress ensures good quality. Parents should carefully consider the crib size mattress dimensions to prevent mishaps due to unsupportive mattresses. 


A firm mattress doesn’t necessarily mean a hard mattress. A firm mattress is essential as it doesn’t sink in quickly. Most importantly, it mitigates the risk of sudden infant death syndrome. The baby’s body gets proper support for its body posture. Soft mattresses may cause babies to slip, causing accidents. Thus, firmness should be ensured in a bed while purchasing.


 If the mattress is of poor quality, the lack of proper circulation and temperature regulation may cause infant breathing problems. Most breathing mattresses are safe from dust, moulds, mites, and allergies. Thus, the baby gets a peaceful sleep leading to healthy development as the blood circulation is adequately increased.


The thickness of the innerspring mattresses ranges from 5 to 6 inches thick, and the foam mattress is 4 to 6 inches thick. The thickness should not exceed 6 inches to prevent accidents. 


If you are looking for a mattress to use longer, you must check its durability. A reversible crib mattress can be reliable. One side is firm for babies, and the other is soft and convenient for toddlers. Once your baby is grown up and needs to shift to another bed, flip the mattress, and your toddler bed is ready. Durability shows quality assurance and an investment in your child’s safety. 


Organic mattresses are made of pure cotton and are a healthier option for foams. These mattresses allow babies to breathe comfortably and are non-toxic. Ensure the mattress is 70% organic to serve its purpose effectively.


Some babies do sleep hot. It makes them sweaty waking up in the middle of the night. The innerspring mattress’s coil layer helps dissipate heat and is highly breathable. However, some foam mattresses are also known for cooling and regulating the temperature, particularly for babies’ healthy environment. 


Whatever crib type you choose, the mattress should get well placed in the crib. Besides the things mentioned above, ensure you don’t fill the crib with blankets and stuffed toys, as they can also suffocate the infants. Being mindful while choosing a crib mattress will guarantee that your infant will sleep securely and comfortably.


How big is a crib mattress?

Typically, mattresses range in size from 51 ⅝ to 53 inches in length and 27 ¼ to crib 8 inches wide (thickness can vary between 4 and 6 inches).

Are all crib mattresses the same size?

Standard-sized crib mattresses, mini versions, and unique shapes like circles and ovals are all readily available. The mattress should precisely match the crib, which you will select based on your preferences and the room’s dimensions. There shouldn’t be more than a half-inch space between the mattress and the crib.

Is a crib mattress the same size as a twin?

No, the crib mattress is smaller and shorter than a twin bed. Twin mattresses, which are the most compact of all conventional sizes and measure 38 inches by 75 inches, are very common among small children. Typically, children move from a crib to a twin bed.

Is a toddler bed the same size as a crib mattress?

The size of a “toddler mattress” is 27.25″ W x 51.625″ L, making it the same size as a crib mattress. Firmness and frame type are the two key variations between the two. Mattresses for toddlers may be softer than those for cribs.


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Written by

kritika joshi
Content Writer
6+ years of experience as a content writer. Previously worked as a freelance writer for one of the top mattress brands in India. Well-versed in writing product reviews, product descriptions and content for e-comm sites.

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