Swaddles vs Sleep Sack: When and How to Use Them!

I get a lot of questions about swaddles vs sleep sacks. And honestly, even if you’re not a first-time parent, it can be confusing to know what the difference between the two is, and when to use each one.

Also, there are so many different kinds of swaddles and an equally shocking number of different sleep sacks. Really, how can having a baby be so confusing?! Can’t we just make sure they are clothed enough to be warm, stick them in a safe sleep space (which is more than we can say for what was done 100 years ago), and just be done with it!? 

You could.

However, after working with thousands of babies, I have seen firsthand the benefits of swaddles and sleep sacks. They truly do make a difference in baby sleep, and they are much safer than using a blanket to keep your little one warm. Once you understand the difference between swaddles and sleep sacks, and know when and how to use each one, using them will be as second nature as putting on a bib before each meal. Or socks before shoes. Or those little scratch mitts before a car ride. Actually, scrap that, no one ever uses those. 

In this blog, I will cover: 

What is the difference between swaddles vs sleep sack?

Why should I use a swaddle? 

Why should I use a sleep sack?

Are sleep sacks safe for newborns? 

Do I use a swaddle or a sleep sack? 

When and how to transition from a swaddle to a sleep sack

How to transition out of a sleep sack 

What is the difference between swaddles vs sleep sack?

Swaddles vs sleep sack; what are they and which is best? There are so many different kinds of each one out there on the market, and it’s really not clear what the difference is. So let me break it down for you. 



Baby who is swaddled |The Peaceful Sleeper

Swaddling is when you wrap your baby up so they are warm, snug, and feel like they’re back in the womb. Swaddling is done by either using swaddle blankets, or many different companies make swaddles that are secured using Velcro. 

Usually you swaddle a baby so the baby’s arms are at their sides as this helps with their Moro reflex (more on this later). Once it is time to start thinking about transitioning out of a swaddle, you can swaddle with one or two arms out (this way your baby can begin to learn to self-soothe with their hands). 

You can swaddle a baby from the time they are born until they begin to roll. We don’t want to be swaddling babies once they can roll as it would be a suffocation risk; if they rolled to their stomach when swaddled, they may get trapped faced down. The AAP says that swaddling is safe as long as it is done correctly. This means that we want to make sure that whatever type of swaddle is being used, it can’t come loose and cover baby’s face. Also, we want to swaddle babies nice and snug, but not too snug that it restricts hip movement. 

Want to know how to swaddle a baby using a swaddle blanket? Check out my swaddle tutorial here

Sleep Sacks 

Baby in a sleep sack |The Peaceful Sleeper

Sleep sacks are like a sleeping bag or a wearable blanket. They are used once a baby can no longer be swaddled, because they have shown signs of beginning to roll.  Many sleep sacks come with different TOG ratings that determine their thickness/how warm they are. There are lots of handy charts available to help you determine which TOG rating to get, based on the temperature of your child’s room and how much clothing they should wear under the sleep sack.  


I really like this chart! 

Chart showing TOG rating for sleep sacks |The Peaceful Sleeper


Why should I use a swaddle? 

There are a few reasons why I highly recommend swaddling your newborn. One reason is that newborns are happiest when their external environment mimics their environment in the womb. This means that they will feel happy and safe if they are snug in a swaddle. The second reason is that newborns have the Moro reflex, which causes their arms and legs to jerk and flail. This jerking and flailing makes it hard for your baby to fall asleep and stay asleep, however if they are swaddled, it prevents this from happening. 

What some tips for swaddling your baby? Check out my instagram reel below:

Instagram reel on tips for swaddling a baby |The Peaceful Sleeper


Why should I use a sleep sack? 

Most babies begin to roll around 4 months, and the swaddle must be dropped when the rolling starts, however the AAP does not recommend anything in the crib until baby is at least 1 year old. So a sleep sack is a safe option to give your little one a similar feeling of comfort as the swaddle, and it gives some added warmth, without putting a blanket in their crib. 


Are sleep sacks safe for newborns? 

As long as the sleep sack fits properly and cannot come up to cover your baby’s face and the TOG rating is appropriate so they are not becoming overheated, then yes! Sleep sacks are safe for newborns. That being said, I still recommend a swaddle over a sleep sack for newborns as they help your baby feel snug as well as helping mitigate their Moro reflex. 


Do I use a swaddle or a sleep sack? 

To reiterate, I recommend using a swaddle from the time your baby is born, until they are showing signs of rolling. At this point you can transition to a sleep sack, however some babies are still jerky and flail their arms, which disrupts their sleep. Thankfully there are some really great products on the market which can help with this transition, such as the Dreamland Baby’s weighted swaddle, Swaddle Sleeves Sack or Merlin’s Magic Sleep Suit. (More on how to make this transition later.)

It is still important to check what the safety recommendations are for each sleep tool that you use, do your own research and choose a product you are comfortable with. For example, you need to stop using the Merlin’s Magic Sleep Suit once your baby is able to roll when they are IN it.  And with the Dreamland Baby’s weighted swaddle, some parents are not comfortable using a weighted product. Of course, I always encourage you to make the best decision for your family. For more info on the safety of using weighted products, read the disclaimer at the bottom of this post. 

Related Reading: When to Stop Swaddling a Baby

When, and if your baby is no longer jerky, and you don’t feel they would benefit from the added comfort and gentle weight of these products, then you can move to a regular sleep sack that has an appropriate TOG rating and is a good fit for your baby.  However, I will say that I personally LOVE Dreamland Baby’s weighted swaddle and sleep sack as a long term sleep sack. The gentle weight of both products helps calm and relax baby so they fall asleep faster and stay asleep longer. However, it’s a personal choice! 


When and how to transition from a swaddle to a sleep sack


How do I transition from a swaddle to a sleep sack?

As I mentioned, you need to stop swaddling your baby when they show signs of rolling. Most babies become used to being swaddled and love it, so dropping the swaddle can cause some sleep disturbances. As I mentioned above, there are a few amazing products out there that are great at helping with the transition.


1. I love the Dreamland Baby’s weighted swaddle because not only does it help reduce the Moro reflex, but the weighted aspect increases serotonin and melatonin while decreasing cortisol, and it can be used as a swaddle as well as a sleep sack! (This link get’s you 15% off!)

2. Merlin’s Magic Sleep Suit is a great short term solution to this transition, as your baby’s arms are no longer at their sides, however the suit is puffy which gives your little one a similar feeling to being all wrapped up. It mitigates the Moro reflex however you need to ditch it once your baby can roll IN it. 

3. Swaddle Sleeves sack is another great transition tool as the detachable sleeves are gently weighted. It helps with jerky arms and once your baby is rolling while wearing the weighted sleeves you can replace one or both weighted sleeves with the regular sleeves. (This link gets you 10% off!)

For more tips and tricks on transitioning out of a swaddle, check out my instragram reel below:

Instagram reel on transitioning from a swaddle |The Peaceful Sleeper



When do I stop using a sleep sack?

There are a couple of things to consider when deciding the appropriate time to stop using a sleep sack. Since sleep sacks are safer than a blanket, there really is no reason to ditch it until your little one is in a big kid bed. The AAP says that once your baby is older than one, you have the option of transitioning them out of the sleep sack and introducing a small blanket, however, there are benefits to continue using a sleep sack instead of a blanket. 

One benefit is that wearing a sleep sack makes it difficult for your little one to climb out of the crib. (And I don’t recommend transitioning to a big kid bed until at least 3 years old). 

The other benefit is that unlike a blanket, your little one can’t get tangled up in the sleep sack, nor will they get frustrated in the night trying to find it if they’ve gotten cold. Once your little one is in a big kid bed, you probably want to consider transitioning them to a blanket instead of a sleep sack, simply for ease of movement getting out of bed. It’s a little tricky to get out of bed at night to find your parents/get a drink/go potty if you’re zipped up in a sleeping bag. 


How to transition out of a sleep sack 

Toddler not in a sleep sack |The Peaceful Sleeper

There is no right or wrong way to transition out of a sleep sack, and most children have very little difficulty with the transition, however if you are concerned or want to air on the side of caution, consider a slow transition. 

Introduce your little one to a small, light blanket to go with their sleep sack so they get used to manipulating the added material, in their sleep space. It also might be easier to make this transition while they are still in their crib, and then once they are used to sleeping with a blanket instead of a sleep sack, then make the transition from crib to a big kid bed and ditch the sleep sack.

For everything you need to know about transitioning your toddler from a crib to a big kid’s bed, check out my “Transitioning to a Big Kid Bed” troubleshooting guide, which is in my Toddler Guide Pack



Recap on Swaddles vs Sleep Sack

Baby swaddled with parents |The Peaceful Sleeper

There is a difference between swaddles and sleep sacks, and each one has a valuable time and place in your little one’s sleep journey. The most important things to keep in mind are the safety guidelines around when and how to use each product. If you have more questions, grab a 30 or 60 minute consultation with one of our amazing sleep consultants! They would love to help you with any questions you may have! 

Speaking of when, have you signed up for our Free Email Series yet? I send you the exact sleep tips, recommendations, and advice that you need, right when you need it! I’m talking about when to drop the swaddle, when to transition to a big kid bed, what to do when those regressions hit, and so much more! Click here and enter in your little one’s birthday for perfectly timed sleep help!


Disclaimer about using weighted products: According to the 2022 AAP updated recommendations, “It is recommended that weighted blankets, weighted sleepers, or other weights not be placed on or near the sleeping infant. A single crossover randomized nonblinded trial of 16 infants with neonatal abstinence syndrome found no adverse events when a 1-pound weighted blanket was placed on each infant for 30 minute observed episodes. However, no studies have documented the safety of weights for infants in an unobserved, nonclinical sleep environment.” 

We at The Peaceful Sleeper believe in doing what feels best for you and your family. Since there have been no documented adverse “events” from using weighted sleep products (at the date of posting this), and no studies that prove that using a weighted product is unsafe (at the date of posting this), some parents feel comfortable using a weighted product and others do not. We always advocate for doing your own research, staying informed on up-to-date safety recommendations, and making an informed decision that’s best for your family.

You can find the full 2022 AAP guidelines here, and the study they used as evidence for their weighted product recommendation here. 

Christine Lawler

Christine Lawler

MS, LMFT, Certified Pediatric Sleep Consultant

Hi! I’m so glad you’re here! I’m a Licensed Marriage and Family Therapist, practicing for over 13 years. I’ve set out to do ALL of the research and I created a method to optimize baby sleep that is tuned in, empowering and WORKS. There absolutely should be joy in motherhood, and I have learned that every baby CAN get better sleep!

Read more about my team here.

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