How Long Do Babies Use Sleep Sacks?

How Long Do Babies Use Sleep Sacks?

Baby Sleep Sacks: Usage, Timeline & Outgrowing

If you haven’t jumped on the sleep sack bandwagon yet, you’re going to want to as soon as possible. Sleep sacks are a fantastic tool for keeping your baby warm and comfortable during the night in a way that is completely safe.

Some parents, however, are likely to have questions about these sacks, like what they are exactly, are they safe and how long do babies use sleep sacks.

Keep reading for the answers to these questions and more.

What’s a sleep sack?

A sleep sack, also known as a wearable blanket, is like a sleeping bag for babies and toddlers. Some come with a swaddle incorporated, but generally they have armholes that allow babies and kids to move their arms freely along with a zipper to close the blanket, sealing in warmth and ensuring there isn’t any loose fabric in the crib or bed. 

Are sleep sacks safe?

Sleep sacks are safe to use and they also improve the overall safety of your child’s sleeping environment. The design not only reduces the risk of SIDS and keeps them safer at night, but it also prevents their little legs from getting stuck in the crib bars or between the crib and the mattress, which can lead to leg injuries.

The Center for Disease Control even advises parents: “If you’re worried about your baby getting cold during sleep, you can dress them in sleep clothing, like a wearable blanket.”

Baby Sleep Sacks: Usage, Timeline & Outgrowing

When should babies start wearing sleep sacks?

Sleep sacks are entirely optional. You can dress your baby in pajamas, a onesie or give her a wearable blanket—it’s entirely up to you. That being said, your baby can start wearing a sleep sack pretty much from birth. As long as the sack is the appropriate size for your baby, he or she can reap the benefits and you can rest easier. 

Why do babies need sleep sacks?

Babies like to feel warm and snuggled like they were in the womb. It makes them feel safe and comfortable so that they will sleep more soundly for more extended periods. If you’re wondering how to tell if your baby needs a sleep sack, you can certainly put her to bed with one and then without one and see how she sleeps. Parents who are worried about their babies being cold at night will most definitely benefit from the peace of mind a sleep sack offers.

Swaddles can be used in the early days, but as soon as a baby can roll over or kick enough to unwrap the swaddle, it becomes a potential suffocation hazard. Sleep sacks solve this problem by offering that same warmth and comfort without the danger of suffocation. 

When should babies stop wearing sleep sacks?

If you’re wondering how long should a baby wear a sleep sack, the answer is simple: there is no real cut-off date for how long to use a sleep sack for a baby, but, generally speaking, you can use one until your child is no longer comfortable wearing it. Today you can choose from a huge range of sizes and designs, with wearable blanket options from the newborn phase through toddler stages.

Of course, babies should never wear a sleep sack that they have outgrown and they should always be temperature appropriate. 

You may also notice that your baby simply doesn’t like it anymore. If they have reached a point where they want to explore and want maximum mobility, they may see the sleep sack as holding them back. 

Why do babies not need sleep sacks anymore?

When your baby is one, you have the option of leaving a small, lightweight blanket in his or her crib without it being a suffocation hazard; however, if your child likes his or her sleep sack, you most certainly can continue using it.

Sleep sacks won’t be necessary if you can’t find the appropriate size or if your baby feels too restricted. If you’re wondering how to tell if your baby doesn’t need a sleep sack anymore, your child will tell you. 

She will be able to roll over in a sleep sack but she won’t be able to crawl when wearing one. If this frustrates your baby or toddler, you might be met with resistance when you try to put on the sleep sack.

Sleep sack factors to consider

When you start and stop using a sleep sack is entirely up to you, but there are a few things to consider which may help you make a decision.


Is there a sleep sack that fits your baby properly? A sleep sack should be loose enough to move around but not so loose that it can cover your baby’s face. On the other hand, if it is so tight that it hinders movement, it is time to move up in size or stop using the sack. 


Sleep sacks are made from different materials, and some are warmer than others. Ensure that you get a sleep sack that is appropriate for the season and dress your baby in seasonally appropriate clothing while he or she is wearing the sack. 


While most sleep sacks have a fairly standard design, some have distinguishing features that may allow parents to keep babies in them longer. Two stand-out features are sleep sacks with sleeves that are better suited for colder environments and sleep sacks with side zippers and open bottoms, which are great for toddlers who want to use those feet the second they wake up.  

It’s a personal decision

As you can see, the easy answer to the question when do babies stop sleeping in sleep sacks is that it is a little up to the baby but mostly up to the parents. 

If there were a rule about it, it would have to be that sleep sacks are no longer needed from a safety perspective after your child’s first birthday when he or she can safely use a blanket. That being said, your child can certainly continue to use one through the seasons and  developmental milestones as long as they are happy and comfortable.

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