The 8 Best Sleep Sacks for Baby to Have a Safe, Cozy Night’s Rest
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QUICK SUMMARY
The best sleep sack is the Halo SleepSack Wearable Blanket according to parents on the What to Expect staff and in the What to Expect community who say it is soft, lightweight and easy to use.
While our ancestors may have wrapped their little ones in thin cloth, today's marketplace is filled with products that do much of the swaddling work for you. If you find the idea of swaddling your newborn daunting, like I did when I had my first child, or you’d prefer to have an easy-to-use alternative for middle-of-the-night changes, consider a baby sleep sack instead.
The idea of a sleep sack is the same as a swaddle: to provide security, comfort and a snug feeling for little ones to help them rest easy on their own.
As a mom of two who has used sleep sacks with both of my sons, I can attest to how much of a lifesaver they can be, especially in the early days. A baby sleep sack is easier to use than a swaddle, yet provides a similar cozy, comforting environment for a good night’s sleep. And, they’re great for using past the swaddle stage — even once they start moving around at night, a sleep sack that frees baby’s arms is safe to use so they can stay warm without getting caught up in any excess material in their crib, which could pose a suffocation risk.
How we chose the best sleep sacks
Safety is a top priority when it comes to any sleep-related product. To learn what features to look for in a sleep sack, and how to safely use one, I consulted the safe sleep recommendations from the American Academy of Pediatrics (AAP) and spoke with spoke with four pediatricians:
- Gina Posner, M.D., F.A.A.P., a board-certified pediatrician practicing at MemorialCare Medical Group in Fountain Valley, California and member of the What to Expect Medical Review Board.
- Micah Resnick, M.D., F.A.A.P., a board-certified pediatrician in Cincinnati, Ohio, with TriHealth and member of the What to Expect Medical Review Board.
- Elizabeth Murray, D.O., F.A.A.P., a pediatrician at the Golisano Children’s Hospital at the University of Rochester.
- Gary Kramer, M.D., F.A.A.P., a pediatrician based in Miami, Florida.
The doctors and the AAP advise against weighted sleep sacks, which helped narrow down the choices for best sleep sack.
After consulting the experts, I wanted to learn directly from moms all about what sleep sack features they appreciate and which specific products they’d recommend to first-time parents. I looked at feedback from the over 1,900 parents who voted for their favorite sleep sack in the 2023 What to Expect Sleep Awards. I also spoke with three What to Expect staff members and, of course, leaned on my own experience using several sleep sacks with my two sons.
Based on this feedback, I narrowed this list down by highlighting the sleep sacks most praised for their soft, lightweight material and ease of use (especially at nighttime).
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Best Sleep Sack Overall
Halo SleepSack Wearable Blanket
- Soft and lightweight
- Trusted brand
- The zipper can lose its integrity over time with frequent washings
When to use it: This sleep sack is appropriate for newborns, older babies and toddlers, although most parents prefer to use it after the 3- to 4-month mark. The brand's SleepSack Swaddle is a better fit for newborns.
Material: 100 percent cotton
Size range: Newborn-XL
Halo’s original SleepSack is both a What to Expect Sleep Award- and What to Expect Mom Must-Have Award-winner for a reason: It’s the perfect wearable blanket. The sleeveless design keeps baby from overheating, while 100 percent cotton fabric keeps baby comfortable. It’s also easy to use: Unlike other sleep sacks that secure with crinkly Velcro or hard-to-use snaps, Halo’s has an inverted zipper for easier diaper changes.
More than any other product, Halo SleepSacks have become a constant feature of the baby years for my two children (now 3.5 and 1.5 years old). If I could go back in time, I’d put three of these in every size they offer on my registry. My younger son, now a size large, still wears one of these sleep sacks every night. In fact, he’s reusing many of the same ones his older brother wore a few years earlier, which speaks to the quality of the material.
Sarah Darby, What to Expect’s Senior SEO Strategist and mom of a 1-year-old, is also a fan of these sleep sacks. “I love a few things — the different TOGs, so I could choose the right one for the weather, the patterns (especially gender neutral), the price was reasonable compared to others and the quality is great,” she says.
Keep in mind that the brand offers a variety of wearable blankets, but this style is "arms out," meaning it's best for little ones who can roll over and don't need their arms pinned down the way a traditional swaddle blanket does. This style is available in sizes small (for babies up to 18 lbs. or 26 inches long) to extra large (for toddlers up to 36 lbs. and 40 inches long).
Parents love how soft and lightweight the fabric is, although some report that the zipper eventually breaks and has to constantly be rethreaded. In my experience, this tends to happen after many, many wears and washes, buthang-drying it seems to help the zipper last longer.)
Best Transitional Sleep Sack
Sleeping Baby Zipadee-Zip
- Transitional item that grows with baby
- Over 35 colors and patterns available
- More expensive than others on this list
- Made of polyester
When to use it: This sleep sack is appropriate for babies 3 months and older, although most parents prefer to use it during the transition between traditional swaddle and regular sleep sack
Material: 96 percent polyester/4 percent spandex
Size range: XS (3-6 months) - XL (2T-3T)
Graduating out of a swaddle and into an arms-out wearable blanket can be a challenge for little ones. The Sleeping Baby Zipadee-Zip Sleep Sack is designed to help ease your baby through this transition.
This product has a unique starfish design, à la Maggie Simpson’s snowsuit, allowing your baby to safely roll over and wiggle around while still enclosing her in a safe wearable blanket. The fabric has a slight resistance in the arm area, which helps deliver the secure, cozy feeling of a swaddle. It also has a huge range of cute designs and fabrics to choose from.
Some What to Expect parents report that it took a few nights for their babies to get used to the roomier feeling of the Zipadee-Zip, especially when transitioning from a regular swaddle or swaddle-like sleep sack. This sleep sack is also mostly made of polyester, a fabric some parents prefer to avoid in favor of more breathable materials such as cotton or bamboo.
Best Sleep Sack for Arms-Up Sleepers
Love to Dream Swaddle Up Original
- Swaddles while still letting babies have some arm movement
- For a limited age range
When to use it: This sleep sack is appropriate for newborns, but because it restricts the arms, it should be retired after the 3- to 4-month mark when your baby shows signs of rolling
Material: 93 percent cotton, 7 percent elastane
Size range: Newborn-Large
Did you know that many babies like to sleep with their arms up when they’re lying on their backs? Unlike some other wearable blankets, Love to Dream’s Swaddle Up is a sleep sack-swaddle hybrid designed to allow for this sleep position. Another bonus is that this is one of the few swaddle-style sleep sacks for newborns that doesn’t have Velcro wings, which can sometimes be noisy, making it a good fit for fussy or light sleepers.
Because this product restricts babies’ arms, it should not be used once your little one shows signs of rolling over (generally around 3 to 4 months). At that stage, you should transition to an arms-out wearable blanket. If you like the brand, Love to Dream offers sleep sacks for later stages, too: Their Stage 2 sleep sack has zip-off wings to help transition your baby to a sleeveless style, and Stage 3 is an arms-free sleep sack for babies 6 months and older.
Best Organic Sleep Sack
Burt's Bees Baby Unisex-Baby Beekeeper Wearable Blanket
- Organic and breathable
- Great value for the price
- No double zipper
When to use it: This sleep sack is appropriate for newborns, infants and toddlers. Most parents prefer to use it after their baby has outgrown a swaddle or swaddle-style sleep sack.
Material: 100 percent organic cotton
Size range: XS-XL
Everything Burt’s Bees makes — crib sheets, onesies, burp cloths — are made from the brand’s absolutely lovely organic fabric, and these wearable blankets are no exception.
This arms-out sleep sack is 100 percent organic cotton and super soft and breathable, making it a popular choice for warmer weather. It also comes with plenty of legroom, and parents say the design feels nice and roomy. You can choose from three different sizes and a variety of cute prints, but let’s be real — it’s hard to resist the sweet little bee pattern!
Also nice? Many members in the What to Expect community agree that the price is a better value compared to most other sleep sacks. So you can stock up on a few and always have a clean one handy.
One downside is the brand’s zipper, which is one-way. Many parents prefer two-way zippers, which make diaper changes a little easier since you don’t have to fully unzip the sleep sack.
Best Newborn Sleep Sack
Halo SleepSack Swaddle
- Versatile with three-way use
- Easy to use with diaper changes
- The Velcro flaps can become misshapen over time
When to use it: This sleep sack is appropriate for newborns who have not yet shown signs of rolling. Around the 3- to 4-month mark, transition your baby to the brand’s original sleep sack.
Material: 100 percent cotton
Size range: Preemie (1-5 lbs.), Newborn (6-12 lbs.), Small (13-18 lbs.)
Halo’s SleepSack Swaddle is very similar to its original sleep sack, but it has two Velcro flaps that can pin baby’s arms down to combine the benefits of a swaddle and sleep sack in one. The flaps are adjustable, helping to ensure a perfect fit. “The sleep sacks designed with a removable swaddle component are nice as they often last longer since you can remove the swaddle and still use the sleep sack,” says Dr. Murray.
We used the Halo SleepSack Swaddle during the newborn stage with both of my sons, and I can confirm that the Velcro fasteners make swaddling way easier than traditional blanket-folding techniques. Like many other parents, I loved how versatile this sack is. Once my sons showed signs of rolling, we wrapped the flaps around their stomachs and kept their arms out, which meant we didn’t have to retire the sleep sack fully right away.
Your little one can wear this product in three different ways, depending on her age and whether or not she's demonstrated the ability to roll over:
- Both arms in (for the youngest babies, to mimic a swaddle blanket)
- Hands to face (another swaddling-style technique)
- One or both arms out (if your baby is able to roll over, usually about 4 months) before switching to a sleep sack for good
“I inherited many different brands from friends and family members, but started with these because I liked their versatility to use for two arms swaddled, one arm swaddled or both arms out,” says Karen Sly, What to Expect’s Director of Finance and mom of a 3-year-old and 6-month-old. “Both of my babies slept best with only one arm swaddled. Because it had the option to use the swaddle just around their core with the arms out, it was great for when they started to roll and I needed to take that one arm out.”
One more smart feature to appreciate: The inverted zipper opening at the bottom, which allows for quick nighttime diaper changes without needing to take the entire swaddle off.
“It’s very soft and warm,” says Grace Pan, What to Expect’s Product Designer and mom of a 5-month-old, whose daughter was born in the winter. “The bottom is big enough for her to kick.”
However, it’s worth mentioning the Velcro flaps a little more. I loved that they make it easier to create a swaddle-like environment and are far easier to get on and off than snaps. But they can become warped over time, especially if you put the sleep sack in the dryer. In my experience, air-drying it helps them hold up better over time.
Best Sleep Sack for Summer
Kyte Baby Unisex Bamboo Rayon Sleeping Bag for Babies and Toddlers
- Ultra soft
- Buttery and lightweight fabric for warmer nights
- More expensive than other options
When to use it: This sleep sack is appropriate for newborns, infants and toddlers. Most parents prefer to use it after their baby has outgrown a swaddle or swaddle-style sleep sack.
Material: 97 percent bamboo viscose and 3 percent spandex
Size range: 0-6 months, 6-12 months, 12-18 months
For a sleep sack with a lower TOG (and therefore lightweight fabric), What to Expect community members frequently recommend Kyte Baby.
Parents rave about Kyte’s buttery soft fabric. It’s made of 97 percent bamboo viscose and 3 percent spandex, so it’s breathable and light for warmer weather, with a low TOG of just .5. Another nice feature is the J-shaped zipper, which makes it easier to access baby’s diaper for middle-of-the night changes.
The downside is price: Kyte sleep sacks are more expensive than many others on this list.
Best Sleep Sack for Winter
Woolino 4-Season Ultimate Baby Sleep Bag Sack
- Merino wool helps regulate baby’s temperature
- Universal sizing
- Expensive
When to use it: This sleep sack is appropriate for newborns, infants and toddlers. Most parents prefer to use it after their baby has outgrown a swaddle or swaddle-style sleep sack.
Material: Merino wool and cotton
Size range: Universal size fits 2-24 months
Yes, the Woolino 4-Season Ultimate Baby Sleep Bag Sack is expensive. But many What to Expect parents swear by this sleep sack as a good long-term investment: Even though it’s $100, it has a universal sizing system that allows it to fit babies from ages 2 to 24 months, so it can very well be the only sleep sack you purchase for your baby until well into toddlerhood.
What’s more, parents rave about how high-quality the material on this sleep sack is. It has a 100 percent merino wool liner, a highly breathable fabric that’s excellent at naturally regulating body temperature and works equally well in cooler or warmer temperatures. The merino wool is OEKO-Tex 100, which means it has been tested against up to 350 potentially dangerous chemicals, and the outer layer is Global Organic Textile Standard (GOTS)-certified organic cotton. Parents also like the side zipper, which they say gives you more flexibility when changing your baby.
Best Toddler Sleep Sack
Halo SleepSack Toddler Sleeping Bag Wearable Blanket
- Adds an extra layer of warmth along with foot openings for toddlers who need more mobility
- Zipper can become a little warped over time
When to use it: This sleep sack has leg openings, so it’s best for toddlers who 12 months and older who want a little more mobility.
Material: 100 percent cotton
Size range: 12-24M, 2T, 3T
If you thought there was nothing cuter than your baby in a sleep sack, just wait until you see your tot toddling about in Halo’s SleepSack Sleeping Bag. This product, which is almost like a sleep suit, is designed for older toddlers who have outgrown the brand’s original sleep sacks. It combines the roomy, blanket-like environment of a sleep sack with the flexibility of pajamas.
We switched my older son to this wearable blanket when he was around 2 years old, and he continued wearing it for another six months. I liked that it added an extra layer of warmth on cooler nights and somewhat restricted his legs, which I think helped prevent him from attempting to scale the walls of his crib. (I don’t think it’s a coincidence that he figured out how to climb over it shortly after he outgrew this product.)
This wearable blanket is made of soft, 100 percent cotton with leg openings, which gives your toddler some extra mobility. There are also convertible foot openings that can be flipped over to keep her feet warm on cooler nights.
Like other Halo sleep sacks, some parents struggle with these zippers, saying they get a little warped over time with frequent washings. In my experience, this one has held up better than the zippers on the original sleep sacks, however.
What to look for when buying a sleep sack
When you're looking to buy a sleep sack for baby, these are the most important factors to consider:
Type: There are two main categories of sleep sacks to choose from. The first, sleeveless sleep sacks, are designed so baby can have her arms out while the rest of her body is contained in a closed sack. This style can typically be used safely for babies long after they’re able to roll over because it keeps their arms free.
Swaddle-style sleep sacks, on the other hand, have extra fabric flaps that are secured around her arms to swaddle her. “They are designed to stay snug and not move up over baby’s face,” says Dr. Murray. (Some models mimic swaddling by giving baby covered sleeves to hold her arms instead.) Like a traditional swaddle, these are not safe to be used once baby can roll over — usually around 4 months — unless the design of the bag can convert to keep her arms free.
Material: Sleep sacks are available in a slew of different styles and materials, so make sure you choose one that’s best for the season you’re in. “Look for a comfortable soft fabric,” says Dr. Resnick. Cotton or bamboo are great choices, because they’re breathable and soft. As mentioned before, you should also always avoid any weighted sleep sacks, per AAP safe sleep guidelines.
When searching for sleep sacks, you might come across the term “TOG,” which stands for Thermal Overall Grade. This is a measurement of warmth in sleepwear products, and a lower TOG rating means the fabric is lighter and may be better for hot weather.
Size: Again, some wearable blankets can adjust to your growing baby’s needs, while others come in a set size. You want to make sure the sleep sack fits baby comfortably so that they’re not too squished inside of the blanket, but not so loose that your baby could potentially kick it off or be smothered, says Dr. Kramer.
Ease of use: The beauty of sleep sacks is that they don’t require any special wrapping, so they’re often easy to use. You may have to do some trial and error, though, to figure out what designs are best for you: Sleep sacks can come with Velcro, snaps or zippers.
FAQs
What is the difference between a sleep sack and a swaddle?
Swaddling is an age-old technique for wrapping babies in a blanket in order to replicate the feeling of being in the womb. It involves tucking the folds of a small, lightweight swaddle blanket around your baby to keep her cozy and warm while she sleeps. (If you’re unsure how it works, here’s a helpful step-by-step tutorial.)
Although swaddling offers many benefits — it helps your baby feel safe and secure, and prevents her from flailing her arms and legs — the technique can be tricky to master. You also should stop using a swaddle once your baby starts to show signs of rolling, which usually happens around 3 to 4 months. That’s where a sleep sack comes in handy.
Sleep sacks, also known as wearable blankets, create a cozy, blanket-like environment that won’t get tangled or slip off the way a regular blanket can. While wearing a sleep sack, your baby’s arms can either be out (in a sleeveless sleep sack) or tucked down (in a swaddle-style sleep sack, which is only appropriate for newborns who haven’t shown signs of rolling).
Sleep sacks are easy to put on your baby, eliminate the steps involved in swaddling and are secure. “They are easier to use, with no fancy or complicated wrapping,” says Dr. Resnick. “They can make middle-of-the-night diaper changes easier.”
How do sleep sacks help baby?
Like a swaddle, a sleep sack can help your baby feel secure and calm, add a layer of warmth on cooler nights, and prevent her from flailing her arms and legs, which can trigger her startle reflex and potentially cause her to wake up. But sleep sacks also offer some distinct benefits over swaddles:
- They’re easier to use. Swaddling is a technique that can be tricky to master, but wearable blankets are basically foolproof to put on even a very wiggly baby.
- Your baby can use them for longer. A traditional swaddle blanket can only be used until your child starts to show signs of rolling. But sleep sacks can be worn for much longer — some brands offer sizing up to the toddler years.
- They’re available in a wide range of styles and materials. A thicker cotton sleep sack can keep your little warm one in cooler temperatures, while linen sleep sacks are ideal for hotter climates. Sleep sacks are also available in a number of different designs, so you can try a few to find one that your baby seems to like best.
- They’re more secure. Swaddle blankets can loosen and fall off, especially as your baby gets older and moves around more at night. Sleep sacks, on the other hand, are securely fastened for a snug fit all night long.
Are sleep sacks safe?
Sleep sacks are the safest way to provide an extra layer of warmth for your sleeping baby, experts say. “Since traditional blankets are deemed unsafe for children under 1, swaddling or sleep sacks are a great alternative,” says Dr. Kramer
Some sleep sack products are marketed toward preventing Sudden Infant Death Syndrome (SIDS) because they help mitigate some of the risk factors associated with SIDS, such as overheating and blanket tangling.
While the AAP says wearable blankets are preferable to traditional blankets for keeping baby cozy at night, it’s still critical for parents to practice safe sleep hygiene with their babies. Always put baby to sleep on her back and never put anything in her crib (so no pillows, loose blankets, toys, crib bumpers or stuffed animals) until she’s at least 12 months old.
No matter which sleep sack you buy, make sure to follow the manufacturer’s sizing recommendations and usage instructions, as incorrect usage has been associated with injuries. You should also avoid weighted sleep sacks, which the AAP deems unsafe.
Are weighted sleep sacks safe?
You may come across some sleep sacks, suits, swaddles or blankets that are marketed towards infants and have additional weight built into the material. But in 2022, the AAP released updated safe sleep policy recommendations, which included a new warning to avoid weighted swaddles and blankets. Weighted products — weighted swaddles, weighted clothing or weighted objects on or near your baby — aren’t safe, the AAP says.
“Weighted blankets can prevent normal movement of the infant and could potentially provide a greater suffocation risk should the baby roll sideways in one,” Dr. Murray explains, adding that weighted products likely don’t add any real benefits: “Once a baby comes out of the swaddle phase, they are learning to self-soothe as part of a healthy sleep routine. It is normal to have phases of waking during the night and then falling back asleep. Trying to induce deeper sleep is not needed and may be dangerous.”
When should my baby stop wearing a sleep sack?
If your toddler is still comfortable in her sleep sack and your go-to brand has extended sizing, there’s no reason to stop using one, says Dr. Posner. “Some kids will kick off blankets constantly but then they get cold,” she points out. “Sleep sacks can help kids sleep better.”
Another benefit? A toddler-sized sleep sack may make it more difficult for your tot to figure out how to climb out of her crib.
- American Academy of Pediatrics, How to Keep Your Sleeping Baby Safe: AAP Policy Explained, October 2023.
- American Academy of Pediatrics News & Journals Gateway, Pediatrics: Official Journal of the American Academy of Pediatrics, SIDS and Other Sleep-Related Infant Deaths: Updated 2016 Recommendations for a Safe Infant Sleeping Environment, November 2016.
- American Academy of Pediatrics, Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment, June 2022.
- American Academy of Pediatrics, Swaddling: Is It Safe?, July 2022.
- American Academy of Pediatrics, Reduce the Risk of SIDS & Suffocation, January 2017.
- BMJ Journals, Archives of Disease in Childhood, Can Infant Sleeping Bags Be Recommended by Medical Professionals as Protection Against Sudden Infant Death Syndrome?, October 2018.
- Mayo Clinic, Sudden Infant Death Syndrome (SIDS), July 2023.
- National Institutes of Health, National Library of Medicine, Infant Deaths and Injuries Associated with Wearable Blankets, Swaddle Wraps, and Swaddling, February 2014.
- University of Twente, Survey of Prevalence of Protective and Risk Factors for SIDS in the Netherlands, June 2018.
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