Popular keywords

A Guide To Crib Mattress Size


Fact checked

Reviewed by experts

Writers at Sleep Authority are supported by a research team conducting in-depth research about the topics. The editorial team reviews them for accuracy and facts to ensure the most authentic and accurate content is published. Sleep Authority does not offer any medical advice, and you should not rely solely on our content for your course of treatment. Consult your medical professional to discuss any health concerns, chronic conditions, treatment options, or diagnoses.


December 21, 2022

Quick read

6 mins to read

crib mattress size illustration

List of Content

From the diaper storage to the room paint color, from choosing the right blanket for your newborn to buying the right crib mattress for them, parenthood is all about decision-making, and that too, the right ones!

One may have to choose between crib mattress size and crib types and choose the right crib mattress size for their baby(s). In this article, you’ll explore the many factors to consider before choosing the right type of crib mattress size for your little one to sort out this dilemma for you. Read more below…

What Are the Different Types of Cribs?

There are a handful of types of cribs to pick from. Some of the most common cribs are:

  • Standard Cribs
  • Mini Cribs, and
  • Shaped Cribs

An ideal full-size crib mattress should be at least 27 ¼ inches wide and 51 ¼ inches long. The style and color of your baby’s crib combine to become crucial factors. But what needs to be the utmost priority are the crib types.

Standard Cribs

The standard-sized crib mattress is the perfect choice for your toddlers since it does not get small for kids soon since it is big. The standard crib mattress dimensions are a minimum of 27 ¼ inches by 51 ¼ inches for a child’s safety. To ward off coincidental falls, the thickness of the mattress needs to be less than 6 inches. Kids standing on taller mattresses can fall off the mattress while standing.

A standard crib mattress’s dimensions should be 28 inches by 52 ⅜ inches to ensure a more snug fit to the standard-sized crib mattress. Therefore, it is crucial to make sure that the crib size mattress dimensions of the standard cribs match up to the size of the mattress.

Mini Cribs

Since it is difficult to find snug-fit mattresses for mini cribs, the sale of mini crib mattresses is with mini cribs. The crib mattress dimensions for mini cribs are 24 inches by 38 inches. The standard crib mattresses can live for three years, and babies may outgrow smaller mattresses within 18 months. A few of the mini cribs can be doubled over for storage and travel, and they include a lock and wheels to make sure the baby stays in the crib safely. If the baby shares a room with their parents or smaller rooms, mini cribs are considered a better choice.

Shaped Cribs

Some individuals prefer shaped cribs that aren’t rectangular. Adding an adorable touch to your baby’s items gives the room a more welcoming look. If you are not looking for rectangular mattresses, you can choose shaped cribs for your kids. The shapes available include ovals or circles, and the mattresses match the shape of the crib. A shaped crib is a little smaller than a standard-sized crib mattress. Therefore, before purchasing a new crib for your baby, you can check out these uniquely designed elements to add to your baby’s nursery.

How to Choose the Right Crib Mattress Size?

Along with the question of what size is a crib mattress comes the question of how to choose a crib mattress. The options available include a mini crib, a shaped crib, and a standard crib mattress. The mattress can be chosen based on the size of your room and your style. The crib and the mattress on it should fit snugly. The gap between the crib and mattress should be less than ½ inches. The absence of a gap can prevent the baby from suffocating as their head gets stuck. Let us now go through the crib mattress size chart.

Standard Crib Mattress Size

The Consumer Products Safety Commission stated that a standard crib mattress measures a minimum of 27 ¼ inches in width and 51 ¼ inches long and shouldn’t be thicker than six inches. 

A standard-sized crib mattress will be required for standard cribs. The regulated size of standard cribs has extra space in them. From the regulated 28 by 52 ⅜ rectangle, the standard crib can be ⅝ inch smaller or larger. You will have to make sure that your mattress fits the crib properly. It should not be too small or too big. A gap may form if the mattress is smaller and the crib is larger.

Mini Crib Mattress Size

The typical size of a crib mattress is 24 inches by 38 inches. However, the government doesn’t regulate the size of these mattresses, and they are smaller than standard crib mattresses. 

While buying a new mini crib mattress, most individuals can expect it to fit their crib. But since some mini cribs are narrower than others, it is important to check the fit of the mattress before purchasing it. Therefore, it is recommended to research the dimensions of a crib mattress before purchasing it. The research is important since the mini crib mattresses are available in different depths.

Shaped Crib Mattress Size

The shaped crib mattresses usually come along with a mattress that fits it. As for the government regulations and specifications regarding the mattress.

The rule of not too small and not too big applies to all the mattresses, including the shaped cribs. If the shaped crib does not have a mattress, it is recommended to measure the crib for the size of the mattress you require. A tape measure can help in measuring the crib appropriately. You need to ensure that extra space is not present around the edges so that the mattress fits inside the crib properly.

How to Choose a Crib Mattress?

Let us go through the factors for choosing a crib mattress:

  • The thickness of the crib mattress

While foam mattresses have thicknesses between 4 to 6 inches, innerspring crib mattresses have a thickness of 5 to 6 inches. The thickness of the mattress shouldn’t be more than six inches to ensure that the baby does not fall. Both the mattresses can provide support for the comfort of the baby.

  • The price range of the mattress

Usually, a crib mattress can cost somewhere around $150. But depending on the quality of the materials and the features included in the mattress, the price range may become higher or lower. This can be seen with the waterproof covers feature. The presence of this feature makes the price of the crib mattress higher. 

  • The firmness of the mattress

To reduce the chances of Sudden Infant Death Syndrome, it is better to have a firmer mattress for babies. Every year due to SIDS, around 2500 infants die. Firmer mattresses reduce the chance of suffocation that causes the unexpected death of an infant. It is a firm mattress if it snaps back immediately after pressing on the edges and center. This firm mattress is safer for your baby. In addition, the resistance offered by the firm mattresses helps babies stand in the crib while they learn how to get up.

  • The breathability of mattresses

The disruptions in sleep because of heat can be prevented by airflow in the mattress. The bed stays cool due to the air circulation inside the mattress in the coils of the innerspring mattress. The preferred choice is to use an all-natural latex mattress. 

Due to the number of chemicals in organic crib mattresses. The organic natural materials can be ensured by checking for Global Organic Latex Standard and Global Organic Textile Standard labels.

  • The durability of the mattress

Buying a reversible mattress can be better for long-term use. The firm side of the mattress can be used for infants, and the softer side of the mattress can be used for toddlers. The toddler mattress size is similar to a crib mattress. The transition from the firm to the soft side should be made after confirmation from the pediatrician. The toddlers feel more comfortable while sleeping on a less firm mattress.


This article answers many of your questions, including what size a crib mattress is, the types of crib mattresses, and the dimensions of a standard-sized crib mattress. Along with the sizes of crib mattresses, we went through some tips that should be followed before buying a crib mattress. And with the option of twin vs. crib mattress size, a crib mattress is shorter and narrower than a crib mattress.

All in all, the chief concern before purchasing a crib mattress is to ensure that your mattress is comfortable and supportive for your baby.


The size of a crib mattress may vary based on various reasons. Among these, the standard size of mattresses has been set up. This size measures a crib mattress with 51 ⅝ to 53 inches in length and 27 ¼ to 28 inches in width. The thickness of the mattress can vary. It needs to lie between 4 to 6 inches.

All crib mattresses don’t have the same size; the size may vary anywhere from 51 ⅝ to 53 inches in length and 27 ¼ to 28 inches in width.

If we talk about twin vs. crib mattress size, a crib mattress is shorter and narrower than a twin mattress.

The standard toddler mattress size is close to a crib mattress.

Is this article helpful?

This website does not offer medical advice nor professional medical services; rather, it is provided solely for educational, informational, and/or entertainment purposes. Individuals seeking medical advice should consult a licensed physician. The information provided should not be used for diagnosis or treatment of any condition, disease, or injury. When you have a medical condition, you should always talk to licensed doctor or other certified medical professional.  You should never delay seeking professional medical advice or treatment based on the contents of this website.  Call 911 or immediately go to the nearest emergency room if you think you may have a medical emergency.  The contents of this website are provided “as-is”, Sleep Authority and its parent, subsidiaries, affiliates, employees, contributors disclaim any warranty of the information contained herein. Please contact using contact form to report any errors, omissions, misinformation, or abuse.

More on


www.sleepauthority.com is brought to you by Resident. Our company sells Nectar, DreamCloud, Awara, Level Sleep, and Home Well Designed. While we intend for this site to be an educational and useful resource for consumers interested in sleep-related topics, we also promote our family of brands – brands that we believe in – on this website. Where we have commissioned independent research and/or articles to support our content, we will state as such in the sub-heading of the article. Where we compare our brands and products against others, we will provide the review criteria as well as state our basis for choosing the “best” or “top” product in a link accompanying the comparison. Our aim is to assist consumers in choosing the best solution for getting restful and comfortable sleep and it is our belief that there is a Resident product that meets any sleeper’s needs.