Crib Mattress Size

Written by Mohammed Aftab

Last Updated March 13, 2024

Infants tend to require anywhere from 13-16 hours of sleep each day, and providing them with a suitable mattress is a parent's prime duty. Thus, choosing the right crib mattress size for your baby, along with considering other mattress qualities, becomes a crucial aspect when buying a crib mattress.

latex mattress

Our guide on crib mattress sizes aims to impart knowledge on crib mattresses, the different sizes they're available in, what size you should be choosing for your baby, and what other qualities you must consider when buying crib mattresses.

Key Takeaways:

  • Choosing the right crib mattress size is crucial for ensuring a proper fit inside the baby's crib, minimizing the risk of entrapment, and creating a safe sleep environment for the baby.
  • Opt for a 'firm' crib mattress to reduce the risk of Sudden Infant Death Syndrome (SIDS). The recommended mattress thickness is no more than 6 inches to prevent climbing and potential injuries.
  • There are two main types of crib mattresses - all-foam and spring mattresses. Organic mattresses are recommended due to the healthier materials they use.
  • Besides size, parents should also consider factors like breathability, certifications, durability, waterproofing, bedding accessories, cost, and regional variations when purchasing a crib mattress for their baby.

baby in a crib mattress

What Is a Crib Mattress?

A crib mattress is a type of mattress meant to aid and accommodate young children. They're smaller compared to standard mattress sizes, like twin beds, and are designed to fit inside the interior dimensions of a baby's crib.

A baby's crib mattress is where they spend a significant amount of time sleeping during their early years. The primary purpose of a baby mattress is to provide a safe sleep environment, reducing the risk of issues like Sudden Infant Death Syndrome (SIDS).

Crib mattresses are usually designed for use by newborns, infants, and toddlers up to the age of about 3-5 years old. After this point, the baby crib mattress is usually no longer suitable for their needs, and it's time to consider something larger (like a twin bed).

How Big Should a Crib Mattress Be?

According to the US Consumer Product Safety Commission, a full-size (or standard) crib mattress size should measure at least 27 1/4 inches wide and 51 5/8 inches long. These dimensions are set to ensure a proper fit inside a standard full-size crib, minimizing the risk of entrapment and creating a safe sleep environment for the baby.

Manufacturers may either choose to make a standard crib mattress measuring 27" x 51" or 28" x 52". For consistency's sake, we shall use the measurements of 28" x 52" for the rest of this guide.

What Is the Recommended Firmness and Thickness for Crib Mattresses?

Besides the size of a crib mattress, its firmness and thickness are two essential aspects that you just cannot ignore.

ideal mattress firmness and thickness

For the ideal mattress firmness, opt for a 'firm' mattress option. Soft mattresses can often be a factor in Sudden Infant Death Syndrome (SIDS). Firm mattresses mitigate the risk of a baby sinking into the bed and being asphyxiated (suffocated).

For the ideal mattress thickness, opt for no more than 6 inches. The recommended mattress thickness is usually sufficient to provide comfort and support for the baby. Going for a thicker mattress above 6 inches may risk the baby climbing over the crib walls and falling.

Crib Mattress Size Chart

Crib Mattress Size (Name) Dimensions (Inches)
Standard Crib Mattress 28” x 52”
Mini Crib Mattress 24” x 38”
Shaped Crib Mattress Varies Depending on Crib Shape.
(Circle, Oval, Square, Hexagonal, etc.)

Standard Crib Mattress: Standard crib mattress dimensions span 28 inches in width and 52 inches in length. These rectangular crib mattresses are the most common crib size you'll find on the market and can offer sufficient sleeping space for most babies. In some cases, they can even be used for toddlers! The standard-sized crib mattress is also designed to meet safety standards, providing infants with a safe sleeping environment.

standard crib mattress size (with dimensions)

Mini Crib Mattress: The mini crib mattress size spans 24 inches in width and 38 inches in length. Being narrower than standard crib mattresses, they are often used in smaller cribs like mini cribs or portable cribs. Mini crib mattresses are often sold along with mini cribs because, although their dimensions are advertised to be 24" x 38", they can vary from retailer to retailer.

mini crib mattress size (with dimensions)

Shaped Crib Mattress: A shaped crib-size mattress can come in various forms, including square, oval, round, hexagonal, and other irregular shapes to match the uniquely-shaped crib. They are intended to provide a snug fit inside non-standard cribs and can even be custom-designed in many cases. When opting for a shaped mattress, always make sure the mattress fits snugly inside the shaped crib you've chosen.

shaped crib mattress sizes (uniquely shaped)

The Different Crib Types

Baby cribs are available in different shapes and sizes, depending on their utility. When choosing your baby's crib type, knowing about the different types available can also help you choose the right crib mattress size.

  • Standard Cribs

A standard-sized crib measures around 28" x 52" and is the traditional choice for many parents. They have fixed sides, are designed to meet safety standards, and provide a comfortably spacious surface for infants. Standard cribs usually have adjustable mattress heights to accommodate the baby's growth.

Moreover, some standard cribs can be converted to accommodate toddlers as well, saving you from having to buy a separate toddler mattress/bed frame once your baby grows into a toddler.

standard crib

  • Mini Cribs

Mini crib dimensions are smaller than standard crib dimensions. They typically measure 24" x 38" and work great for smaller bedrooms or nurseries. Another use for mini cribs is to accommodate multiple babies under one roof. Getting a standard crib for twins or triplets, especially if you have a small room, may prove to be a hassle.

mini crib

  • Portable Cribs

Portable cribs, also known as travel cribs or playards, are cribs that can be taken with you while you travel. They're often lightweight, small, and easy to fold and store.

Portable cribs are best used as a temporary sleeping solution for parents who often travel with their babies. The convenience they offer triumphs over sizes like the standard crib.

portable crib

  • Shaped Cribs

Shaped cribs refer to cribs that come in unique shapes like circles, squares, or hexagons, separating them from the standard rectangular design. Shaped cribs offer a distinctive aesthetic and can serve as a focal point in the nursery. They can either be found in stores or be custom-designed. When going for shaped cribs, keep in mind that shaped crib mattresses and bedding need to be custom-designed as well.

shaped crib

  • 3-in-1 Cribs

3-in-1 cribs, also known as 4-in-1 cribs, are convertible cribs that you can transform into different bed types as your child grows. They can be converted into a toddler bed, a daybed, and eventually into a full-size (twin) bed.

3-in-1 cribs can prove to be very versatile and useful for your child up until their teenage years. Plus, with their long-term use, they save you the expense of buying a bed frame for your growing child. You may, however, have to spend money on a new mattress every time you transform the 3-in-1 crib.

3-in-1 crib

  • Bassinet Cribs

Bassinet cribs, also known as bassinet co-sleepers, are practical sleeping spaces designed for newborns up to around 4-6 months old.

Bassinet cribs can be placed next to the parent's bed for easy access to the baby during the night. They are often smaller than standard cribs and have a more intimate feel, making it easy for parents to keep their little ones close, especially during nighttime feedings.

bassinet crib

Why Does Crib Mattress Size Matter?

Your baby's mattress size matters for four primary reasons -

  1. To Ensure the Right Fit
  2. To Provide Safety
  3. To Provide Spacious Comfort and Improve Sleep Quality
  4. To Ensure Proper Development

Ensure the gap between the mattress and crib walls isn't over 1 inch! You can test it out by placing your fingers in between the gaps. If you are able to place more than two fingers between the gap between the mattress and the crib, that's a sign that the mattress isn't the right fit.

Large gaps between the mattress and the crib frame can pose a suffocation hazard or entrapment risk for the baby. Choosing the correct crib mattress size significantly lowers the likelihood of SIDS-related incidents.

The standard-size crib mattress is often thought to be the best option, as it provides enough space for most babies to sleep undisturbed. Moreover, studies have determined that an infant's growth can be affected by the quality of sleep they get.

So, choosing the right crib mattress size is not just a suggestion but a necessity for proper development.

natural and organic latex mattress topper

How Many Types of Crib Mattresses Exist?

Broadly speaking, there are two types of crib mattresses: All-foam and Spring.

all-foam mattress vs. spring mattress

  1. All-Foam Mattress: All foam mattresses are exclusively made up of foam materials, which are then encased in fabric. Memory foam, polyurethane foam, and latex foam are usually the three prominent foam types used in all-foam beds. Encasing fabrics can include cotton, polyester, or other soft mattress materials/crib sheets. High-density foam is what we'd recommend, as it provides more support for your baby.
  2. Spring Mattress: Spring mattresses contain a layer of spring as the support core, atop which comes a foam comfort layer. This is then encased in fabric. Modern spring coils, like pocketed coils, are usually the ideal option for the spring layer, while foam like latex or memory foam is used for the comfort layer. Look for a spring mattress with a lower coil gauge number, as it indicates thicker and firmer coils for better support.

You can also find other crib mattress types, like the reversible crib mattress. Also known as 2-stage crib mattresses, they have a dual-sided design, with one side being firmer for infants and the other side being slightly softer for toddlers.

Based on our experience, the best crib mattress type would be an organic mattress. Organic beds, like organic latex beds, use naturally-obtained materials that aren't chock full of chemicals. Therefore, your baby won't be inhaling large amounts of toxic chemicals compared to when sleeping on a synthetic mattress like memory foam.

Look for organic mattresses that are certified by organizations like GOLS, GOTS, and OEKO-TEX. And always remember to buy baby crib mattresses that are sold by reputable retailers, even if they cost a bit more.

Important Factors to Consider When Buying a Crib Mattress

This section will cover all the other important factors you must consider besides crib mattress size.

  • Firmness

A 'firm' crib mattress is essential for a baby's safety and development. It reduces the risk of suffocation and SIDS and helps support their developing bodies.

  • Thickness

A crib mattress should be no more than 6 inches thick. Around 4-6 inches of thickness is recommended. Going above 6 inches of mattress thickness could risk the baby climbing over the crib walls and sustaining an injury.

  • Breathability

Breathable mattresses are integral if you desire to keep your baby's bed cool and hygienic. A breathable mattress allows unrestricted airflow through it, keeping your baby's sleeping environment cool, especially in hot and humid climates.

A mattress's breathability also allows it to prevent moisture retention, a phenomenon that can invite all the allergens in the vicinity and make the mattress unhygienic.

  • Certifications

A certified mattress is often a safe mattress. Certifications from GOLS (Global Organic Latex Standard), GOTS (Global Organic Textile Standard), CertiPUR-US, OEKO-TEX, GREENGUARD Gold, and eco-INSTITUT all stand to verify that the mattress you're using is considered high-quality and non-harmful to human health.

  • Durability

Durable crib mattresses can often last through all the diaper changes and tumbles, and they may even be useful as toddler mattresses or for future siblings! Durable materials, like natural latex, are also highly recommended because they seldom create issues like premature sagging that lead to SIDS-related dangers.

  • Waterproofing

Accidents are abundant when it comes to babies on a mattress, right? Waterproofing the crib mattress is a great way to mitigate permanent pee stains and the dreaded pee smells that prompt you to buy a new crib mattress.

Some mattresses come with waterproof qualities, but we do not recommend them as they could contain unhealthy chemicals. Instead, go for an organic waterproof mattress protector/cover.

  • Bedding Accessories

Do not overdo the amount of bedding you put over a crib mattress. A fitted crib sheet is pretty much all you need for a crib mattress. It's best to avoid using blankets, comforters, and quilts in the crib, especially for very young infants who may not have the ability to move away if they get covered. If you feel the need for extra warmth, use a sleep sack or adjust the baby's clothing layers.

  • Cost

Crib mattresses can cost anywhere from $50-$500 or more. You'll usually find quality choices around the $200-$300 mark. Avoid crib mattresses that are too cheap, as they could be flimsy and risky.

  • Region

Crib sizes and crib mattress sizes can vary according to your region. What we've mentioned in this guide pertains to the USA first and foremost. Make sure to read up on the sizes in your specific region.

natural and organic pillows

Crib Mattress Size FAQs

  1. What size is a standard crib mattress?

A standard crib mattress typically measures around 28 inches wide by 52 inches long. The thickness may vary, but most standard crib mattresses are around 4 to 6 inches thick.

  1. Are crib mattresses all one size?

No, all crib mattresses aren't the same size. The size of crib mattress types can differ, from standard to mini crib mattresses and much more.

  1. Are crib mattresses the same size as toddler beds?

Standard crib mattresses are about the same size as a toddler bed. Most convertible cribs can be converted into toddler beds, and the crib mattress can also be used in a toddler bed.

  1. What is a full-size crib mattress?

A full-size crib mattress is a standard crib mattress that fits a full-size crib, also known as a standard crib. The dimensions are usually around 28" x 52".

Related blog posts:

1. Mattress Sizes Chart and Bed Dimensions Guide

2. California King vs. Queen Mattress Size

3. Twin Vs Twin XL Mattress Size Comparison

4. A Detailed Guide on Full vs. Queen Size Mattresses: Which One Should You Sleep On?

5. Twin vs. Full vs. Queen Mattress Size Comparison

Disclaimer: What is said in this article has been referenced from multiple sources and is intended only for educational and informational purposes. Please note that no content in this article is a substitute for professional advice from a qualified doctor or healthcare provider. Always consult an experienced doctor with any concerns you may have regarding a health condition or treatment, and never disregard any medical suggestions or delay in seeking treatment because of something you read here.