How To Choose The Right Baby Sleep Sack For Your Little One

Mom changing baby

From their first night home from the hospital to the day they graduate to a big kid bed, you’ll want to do everything you can to ensure a safe, comfortable night’s sleep for your little one. A baby sleep sack can provide them with exactly what they need.

In this article, we’ll share what you need to know to choose the best sleep sack for your baby.

Table Of Contents

What Is A Baby Sleep Sack?

baby sleep sack

A baby sleep sack is a safe alternative to a blanket. It’s designed to keep your baby warm by enclosing their torso completely while leaving their arms free to move around.

Sleep sacks became popular in the United States in the 1990s during a major push to combat the rise of SIDS. There was a focus on what could be removed from the sleeping area that might interfere with a baby’s ability to breathe.

Now, safe sleep practices are more commonly known, and a sleep sack can be a part of that.

How Is A Sleep Sack Different From A Blanket?

Sleep sacks can be used from birth to approximately two years old, whereas blankets should not be used at all during the first year of life.

The American Academy of Pediatrics recommends, “Keep loose blankets, pillows, stuffed toys, bumpers, and other soft items out of the sleep space.”

So, if using a blanket is not recommended, then what can keep your little one warm at night? A sleep sack is the perfect answer.

How Is A Sleep Sack Different From A Swaddle?

baby swaddled

It’s important to note that a sleep sack is different from a swaddle and is often used after your baby outgrows the swaddling technique.

Swaddles are only safe until a baby begins to roll over, which is typically between three and four months. At this point, your little one needs their arms free. Sleep sacks allow your baby’s arms to be out so they can push themselves back over or into a more comfortable and safe position.

What To Look For In A Baby Sleep Sack

Natural, Breathable Fabrics

Before you choose the sleep sack that’s right for your little one, think about the materials that will come into contact with your baby’s skin. Cheap fabrics are often treated with harsh or even toxic chemicals that you would never want to expose your child to.

Here are a few of our favorite fabric choices:


Cotton has become one of the most popular choices for baby clothing and sheets. It is breathable and soft against your little one’s skin, and you can be sure that they aren’t going to be exposed to any harmful chemicals.

Because we’re big believers in opting for natural fabrics that are both comfy and safe, the Newton Sleep Sack For Babies is made from organic cotton and bamboo.


Bamboo is extremely durable, luxuriously soft, and very moisture-absorbent. It also protects against UV rays and is hypoallergenic.

Bamboo is naturally stretchy, so it will easily take all those baby squirms in stride. Plus, it won’t irritate your baby’s delicate skin.


Hemp is similar to cotton in the way it feels against your skin. It’s not only soft, but it also becomes more and more comfortable the longer you wear it. Additionally, it can hold 20 times its weight in water and still feel dry to your skin.

Other big benefits are that hemp is UV resistant and provides natural protection from the sun, plus the fabric actively fights against bacteria and fungus.

Merino Wool

100% pure merino wool is woven from very fine fibers to create a soft, breathable fabric.

Merino wool is safe for all skin types, even eczema-prone skin. Research shows that “fine-diameter Merino wool clothing” worn next to the skin “seems to be therapeutic to patients with mild to moderate atopic dermatitis.”

It also has temperature-regulating qualities that make it as useful in summer as it is in winter. In addition, it can help wick away moisture from the skin.

Baby in baby sleep sack


In addition to the right material, be sure the baby sleep sack you choose is the right size for your little one.

It’s perfectly safe for a newborn to wear a sleep sack, but it should be made for an infant. You don’t want any possibility of your baby’s head or face being covered by material that is too large.

However, a baby sleep sack should be roomy throughout the bottom so little feet can kick and squirm. According to the Cleveland Clinic, a baby needs plenty of room for healthy hip development.

According to Dr. Emily Dodson of the Hospital for Special Surgery in New York, “We now know that tightly wrapping an infant’s legs could lead to hip dysplasia, so we recommend a newer, better way of swaddling. The safe way is to use a sleep sack that leaves lots of room for the legs…”

Sleeveless For Safety

If your baby can roll over, they need to have their arms free to flip themselves back over in case they wind up on their stomach while sleeping and can’t breathe.

Temperature Control

Baby sleep sacks can be used all year round. Just keep the material in mind for each season.

You may see the term TOG being used when it comes to baby sleep sacks or other clothing. TOG stands for Thermal Overall Grade and is used in the textile industry to measure thermal properties.

How do you know what the right material weight is for your baby at any time of year?

The higher the TOG rating number, the warmer the item. So a summer weight baby sleep sack TOG rating might be 0.5 — or the equivalent of two sheets. Winter weight baby sleep sacks, on the other hand, may have a TOG rating of 2.0 to 2.5.

The Right Type Of Closure

Snaps can be fairly convenient, but it’s the snapping back up that may become irritating, especially in the middle of the night when you’re sleepy.

You may find that you prefer zipper closures for your baby’s sleep sack rather than snaps. This is particularly true for older toddlers who may learn to unsnap at the shoulders and completely escape the sleep sack.

Zippers that go all the way to the bottom of the sleep sack allow the best access. You can zip out the lower half of your baby, change diapers, and zip them back in without exposing the baby’s chest to the coolness of the room.

Just be sure that the material is high quality and that you check the zipper regularly. A zipper pull can come free from the garment and be swallowed by your baby.

Closed At The Bottom

Baby sleep sacks are closed at the bottom as opposed to gowns, which are open at the bottom. This keeps little legs and feet warm. But the main advantage of a closed bottom is that the material will not ride up and cause any danger of suffocation.

How To Ensure A Safe and Comfortable Night’s Sleep

Mom holding baby in baby sleep sack

Safe sleep is important for your little one. And while it’s important to choose a sleep sack that has all the necessary requirements listed above, it’s also important to follow the American Academy of Pediatrics' safe sleep guidelines.

Safe Sleep Guidelines

  • Babies should be placed on their backs to sleep for the first year of life. Sleeping on their side or on their stomach is not safe (unless they roll themselves into that position).
  • Use a firm sleep surface. Babies should be placed on a firm mattress in a safety-approved crib covered by a fitted sheet with no other bedding or soft objects.
  • Babies should sleep on a separate sleeping surface but in the same room with their parents for at least the first six months.

Choose The Perfect Sleep Sack

baby sitting in sleep sack

Baby sleep sacks are not only a warm and cozy way for your little one to sleep, but they can also keep them safe. In fact, the benefits of sleep sacks are backed by research, and doctors recommend using them.

By choosing the Newton Sleep Sack For Babies, you’ll be well on your way to a safe, comfy sleep environment for your little one! And since getting a good night’s sleep is just as important for your little one as it is for you, take a look at our 100% breathable and washable Crib Mattresses.

With all the tools you need in place, you and your baby will be snoozing safely and soundly every night!