The Essential Baby Sleep Sack Buying Guide for Parents

baby girl wearing cuddle sprouts sleep sack in precious petals

Choosing the Right Baby Sleep Sack 

Ensuring their child gets a good night’s sleep is always a top priority for parents – and for good reason. Getting the right amount of quality sleep is crucial for a baby’s overall growth and development. According to the National Sleep Foundation, infants require 12-15 hours of sleep each day, and up to 17 hours a day for newborns (1). If sleep is among your top concerns for your little one, know that sleep sacks can help you provide them with a safe and cozy sleep environment. 

In this comprehensive guide, we'll explore the world of baby sleep sacks, also known as baby sleep bags, and why they are the perfect solution for your child's peaceful sleep. We’ll help you understand what they are and how, when, and why to use them with your baby. Additionally, this guide dives into the various factors to consider when choosing a baby sleep sack, such as size, material, tog rating, safety features, and styles. 

After reading this post, you’ll feel confident finding the most suitable sleep sack for your baby's needs. 

Cuddle Sprouts baby sleep sack in various colors

The Basics: What is a Sleep Sack for Babies? 

Baby sleep sacks, sometimes called baby sleep bags, are essentially sack-like wearable blankets designed to keep babies warm and safe during sleep. While they are adorable and extra cuddly additions to your baby's sleepwear collection, they provide an innovative sleep solution perfect for aiding in sleep training, transitioning from swaddles, and promoting safe and sound sleep during those first years. 

Benefits and Purpose of Sleep Sacks 

The primary purpose of a baby sleep sack is to create a safe and cozy sleeping environment for infants and toddlers. Unlike traditional baby blankets, which can shift during sleep, sleep sacks offer a secure fit, ensuring the baby’s torso, legs, and feet remain cozy and warm throughout the night. 

According to the American Academy of Pediatrics, babies should sleep without loose objects, including blankets, in their crib during the first year to reduce the risk of sudden infant death syndrome (SIDS) and accidental suffocation or strangulation (2). The innovative design of the sleep sack eliminates the need for loose blankets. Ultimately, these sleeping sacks provide a unique and practical approach to keeping your baby comfortable and safe throughout the night. 

How is a sleep sack different from a swaddle?

While both sleep sacks and swaddles ensure a safe, cozy, and warm sleep environment for your baby, there are key differences in design that parents should be aware of. Swaddles are thin blankets that wrap snugly around a baby like a burrito to provide a soothing womb-like environment for sleep. Parents use tucks and wrapping or Velcro to secure their baby in a swaddle. 

On the other hand, sleep sacks are wearable blankets with a pouch-like design that allows more hip and leg movement vital for healthy development and growth during later months. Similarly, sleep sacks leave the baby’s arms free for natural movement as opposed to the secure wrapping of a swaddle that tucks the arms inside. Additionally, parents like the convenient zipper or snap closures of a sleep sack, making for hassle-free diaper changes. 

While sleep sacks can be used through toddlerhood, swaddles are only safe in the first months of your child’s life. Once an infant starts showing signs of rolling, it’s time to transition into a sleep sack for a safe balance of comfort and freedom. However, some babies respond better to sleep sacks from day one. 

Are sleep sacks safe for babies?

Sleep sacks offer a perfectly safe sleep solution for babies and can help minimize the risk of SIDS, providing a safer alternative to loose blankets in the crib (3). Overall, these sleep sacks are designed to promote safe sleep practices, provide an alternative to or transition from swaddles, and support quality sleep and growth. 

Let’s take a closer look at each of these safety elements. 

  • SIDS: The American Academy of Pediatrics recommendations for a baby’s sleep environment include a firm sleep surface, free of soft bedding or toys. This is where sleep sacks shine. Their design eliminates the need for loose blankets, reducing the risk of accidental suffocation or overheating.
  • Safe Sleep: Sleep training can be challenging for both parents and babies. Baby sleep sacks provide a secure and enclosed environment that minimizes the chances of babies rolling onto their tummies during sleep – a risk factor for SIDS. The unique design ensures your baby stays in the recommended back-sleep position throughout the night.
  • Alternative to Swaddles: As your baby grows and shows signs of wanting more freedom of movement, it’s time to transition from a swaddle to a sleep sack. Sleep sacks offer the security of a snug sleep space without restricting the natural movement of your baby's hips and legs. This transition is crucial for healthy development and helps prevent hip dysplasia.
  • Quality Sleep and Growth: Studies continue to show the correlation between getting enough quality sleep and both cognitive and physical growth in babies (4). Sleep sacks contribute to creating a safe and comfortable sleep space, fostering the optimal conditions for your baby's growth and development.

When should I start using a sleep sack for my baby?

Sleep sacks are a safe and cozy bedtime option for babies from birth through toddlerhood.  While some parents opt for swaddles from day one, watching for signs of rolling is imperative. Many infants start showing these signs around two to four months of age, signaling the need to transition to a sleep sack. Babies can continue to use sleep sacks through the toddler years until they are ready to transition to a big kid bed.

Baby Sleep sack versus swaddle

Factors to Consider When Buying a Baby Sleep Sack 

While sleeping sacks are regarded as safe and comfortable sleeping options for babies, there are a few factors to keep in mind when choosing the right option for your baby. In order to ensure your child’s utmost safety and comfort during sleep, it’s essential to consider important factors like size, fabric, and warmth. Let's delve into these considerations to help you make an informed decision for your little one.

Choosing the Right Size 

Selecting the appropriate size for your baby's sleep sack is more than just a matter of fit; it's about safety and optimal development. Therefore, it’s essential to buy a sleep that is just right – not too loose and not too tight. Here’s why it matters:

  • Safety and SIDS Prevention: Choosing the right size minimizes the risk of sudden infant death syndrome (SIDS) by avoiding loose fabric that could cover airways during sleep.
  • Ideal Comfort and Development: A sleep sack that is too tight can hinder the movement of hips and legs, impacting your baby's comfort and proper physical development.

When shopping for sleep sacks, keep your baby's size in mind. Avoid overly wide arm openings to prevent your baby from slipping their arms inside the enclosed space during sleep. Similarly, ensure there isn’t any excessive space in the collar as the fabric could shift during sleep or cover their airways when lying down. On the other hand, the area around the hips and legs should be loose, allowing for movement. 

To further assist you in making the right choice, we provide a size chart to help you find the best size for your baby, enhancing safety and overall sleep quality. Additionally, we recommend consulting your child’s physician if you have further questions about the size of your child’s sleep sack. 

Cuddle Sprouts baby sleep sack chart

Finding the Right Fabric for Your Baby’s Sleep Sack 

Just as choosing the right size sleep sack is vital for your baby’s safety, selecting the right fabric plays a pivotal role in your baby’s comfort in the sleep sack. The material of a sleep sack plays a crucial role in creating a cozy sleep environment.  Look for sleep sacks made from fabrics boasting the following qualities: 

  • Soft: Provides gentle comfort for delicate skin, promoting a cozy and soothing sleep environment
  • Hypoallergenic: Ideal for sensitive and eczema-prone skin, reducing the risk of irritation
  • Breathability: Promotes natural air circulation necessary for a comfortable sleep experience
  • Thermoregulation: Maintains an optimal body temperature for your baby, preventing overheating or excessive cooling
  • Moisture-Wicking: Draws moisture away from the skin, keeping your baby dry and comfortable

Fabrics that are soft, breathable, and hypoallergenic offer optimal comfort and care for sensitive skin. Meanwhile, moisture-wicking and thermoregulating properties help your baby maintain a cozy and dry sleep environment by minimizing the chances of experiencing night sweats or overheating.  

Pros and Cons of Various Materials

Different materials offer varying comfort levels and suitability for different seasons. While cotton, fleece, wool, muslin, and bamboo are popular choices, they are not without their downfalls.

Cotton and fleece both tend to trap heat, increasing the risk of overheating and discomfort. Wool is often rough and scratchy to the touch and may irritate a baby’s sensitive skin. Muslin and bamboo are lightweight and breathable but might not provide sufficient warmth for colder nights. 

When it comes to baby sleep sacks, there is a fabric that checks all of the boxes to ensure a safe and cozy sleeping environment for your baby. Tencel lyocell is a naturally soft and hypoallergenic fabric that is perfectly gentle on sensitive skin. The fabric also promotes optimal comfort throughout the night due to its superior breathability, thermoregulation, and moisture-wicking properties. Despite its lightweight feel, Tencel is a seasonless fabric, meaning its unique properties can keep your baby feeling snug and cozy all year long. 

That said, the fabric is only part of the equation. It’s important to pay attention to the sleep sack’s TOG for optimal comfort and warmth. 

What does TOG mean on sleep sacks?

TOG, or Thermal Overall Grade, is a measure of the thermal insulation provided by a fabric. Regarding baby sleep sacks, TOG indicates how effectively the material retains heat, influencing the warmth of the sleep environment.

Generally, you can find sleep sacks having anywhere from a  0.2 to a 3.5 TOG rating. When considering the TOG rating for your baby’s sleeping sack, consider the following guidelines of suitable TOG values based on varying room temperatures:

  • 0.2 TOG: Perfect for room temperatures ranging from 75°F to 81°F
  • 1.0 TOG: Ideal for room temperatures between 68°F to 75°F
  • 2.5 TOG: Suited for room temperatures between 61°F to 68°F
  • 3.5 TOG: Recommended for room temperatures below 61°F
  • TOG ratings of 4.0 and above are not recommended for sleep sacks.

Among the available options, the 1.0 TOG stands out as the optimal choice for maintaining an ideal sleep environment. This particular TOG rating is recommended for room temperatures ranging from 68°F to 75°F, ensuring that your baby experiences the perfect balance of warmth and comfort throughout the night.

Are weighted sleep sacks safe for babies? 

While the concept of weighted sleep sacks may seem appealing, your baby's safety should be the utmost priority. Pediatricians advise parents to steer clear of weighted sleep sacks for infants, warning the lack of regulation of these products causes safety concerns (5). 

Instead, focus on sleep sacks with appropriate TOG ratings, ensuring a balance between comfort and warmth without compromising breathability or movement. Always adhere to pediatric guidelines and consult with a healthcare professional.

Other Factors to Consider Before Purchase 

When choosing the perfect sleep sack for your baby, there are a few additional factors to consider beyond size and material. These factors include style and sustainability, ensuring not only comfort and safety but also aligning with your values as a parent.


All sleep sacks share the common purpose of providing a safe and cozy sleep environment for babies. However, various styles cater to different needs. From sack-style to those with legs, swaddle designs, and long sleeves, there's a variety to choose from. The traditional sleeveless sack design is positioned as the most versatile, suitable for year-round use in any climate.

Rather than having multiple styles of sleeping bags for your baby to adapt to various seasons, turn to your baby’s wardrobe for versatility. In colder weather, parents are encouraged to use pajamas, such as footies, and layering for added warmth. In warmer climates, opting for something lightweight like a baby bodysuit as a base layer under the sleep sack is an excellent choice.


In the realm of baby sleep sacks, choosing sustainability isn't just about being on-trend; it's about making a profound statement with every cozy night's sleep. Sustainable materials, like Tencel lyocell, often come from non-toxic and eco-friendly sources. Additionally, they are typically produced with lower environmental impact, helping consumers minimize their carbon footprint.

Furthermore, some parents may be concerned about potential health risks associated with conventional materials, such as flame retardants or exposure to other harsh chemicals during production. Sustainable materials usually adhere to stricter regulations and standards, providing assurance to parents about the safety of the materials they are using with their baby. 

All in all, choosing natural materials, like Tencel lyocell, for your baby’s sleep sacks provides a gentler option for the planet and your baby’s skin. 

Comfortable and Safe for Baby, Convenient for Parents 

Navigating the demands of sleep training for both parents and babies can be challenging. To ease this process, choosing the right sleep sack becomes crucial. Look for characteristics such as a two-way zipper for easy diaper changes, machine-washable materials for convenience, and reinforced stitching for durability. Additionally, consider sleep sacks with zipper covers to protect your baby from potential chafing. These features not only simplify daily routines but also create a secure and comfortable sleep environment, making the sleep training journey more enjoyable for both parents and little ones.

The Best Night Sleep Your Baby Has Ever Had  

Finding the perfect baby sleep sack is a significant step in creating a safe and cozy sleeping environment for your baby. At Cuddle Sprouts, we prioritize the care, comfort, and safety of your baby as we would our own. When first creating our sleep sacks, we knew we wanted to develop a product that both babies and parents would love by supporting a better night’s sleep filled with sweet dreams and cozy comfort.

No detail is too small for us to ensure our sleep sacks provide a peaceful and restful sleep for your baby. Between our convenient design features and premium Tencel lyocell fabric, we know both you and your baby will love it. Shop our collection of baby sleep sacks

To add to your baby’s sweet dreams and sound sleep, check out our soft fitted crib sheets and cozy Tencel baby pajamas.  

Reference Links 

1. National Sleep Foundation, How Much Sleep Do You Really Need? 

2.  American Academy of Pediatrics, Tips for Keeping Infants Safe During Sleep From the American Academy of Pediatrics 

3. National Library of Medicine, Can Infant Sleeping Bags Be Recommended By Medical Professionals as Protection Against Sudden Infant Death Syndrome?

4. National Library of Medicine, Infant Sleep and its Relation with Cognition and Growth: A Narrative Review

5. Consumer Reports, Pediatricians Warn That Weighted Baby Blankets, Sleep Sacks, and Swaddles Are Not Safe

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