The Ultimate Sleep Sack Guide

what-is-a-sleep-sackWhat is a Sleep Sack?

A sleep sack, also referred to as a wearable blanket or baby sleeping bag, is best described as a cross between a blanket and sleeping bag. The unique design allows your baby to stay warm at night while giving them the freedom to move around naturally without getting uncovered and cold. Your little one can do all the kicking and moving around they want but they’ll continue to stay warm and snug. There is no risk of getting entangled as is so common with traditional blankets.

Sleeping sacks for babies have been extremely popular in Europe for over two decades and are just now becoming a well known product here in the US. These wearable blankets are available in sizes from newborns and infants all the way to four year olds. The smallest sizes are often called baby swaddles and their design makes newborns feel snug and secure as if they were still in the womb. Many of the toddler sized sleep sacks have foot openings for mobility when awake but are roomy enough to tuck their feet in at night.

How to Use this Site

With so many brands of sleep sacks now on the market, we wanted to make finding the best sleeping sack for your child (or someone else’s child) as easy as possible. Below are what we believe to be the best baby and toddler sleep sacks as well as baby/infant swaddles. Be sure to browse through our easy-to-read sleep sack reviews using the links in the tables below or the Product Reviews link in the main menu above. Also, check out some of our most popular helpful articles in our Blog.

Best Sleep Sacks for Babies

Room Temp
Woolino 4 Season baby sleep sack Woolino 4 Season
Baby Sleep Sack

63-77° $$$ Our Review
Baby DeeDee Sleep Nest Baby DeeDee
Sleep Nest Baby Sleeping Bag

(lite version
also available)
$$ Our Review
Nini & Pumpkin Moon Cocoon Nini & Pumpkin Moon Cocoon Sleep Sack

65-72° $$$ Our Review

Price:  $ = up to $25   $$ = $25 to $50   $$$ = $50 and over

Best Sleep Sacks for Toddlers

Room Temp
Merino Kids toddler sleep sack Merino Kids
Toddler Sleep Sack

64-80° $$$ Our Review
Woolino 4 Season toddler sleep sack Woolino 4 Season
Toddler Sleep Sack

63-77° $$$ Our Review
HALO Early Walker toddler sleep sack HALO
Early Walker Sleep Sack

     64-68°     $ Our Review

Price:  $ = up to $25   $$ = $25 to $50   $$$ = $50 and over

Best Baby Swaddles

Miracle Blanket Baby Swaddle Miracle Blanket
Baby Swaddle

Cotton Knit
$$ Our Review
Summer Infant SwaddleMe Swaddle

Summer Infant
SwaddleMe Swaddle

$$ Our Review
Woombie Air Ventilated Baby Swaddle

Woombie Air
Ventilated Baby Swaddle

   Bebeflex™ $$ Our Review

Price:  $ = up to $25   $$ = $25 to $50   $$$ = $50 and over


Here are just some of the great benefits that sleep sacks provide:

  • The perfect combination of comfort, convenience, and safety.
  • Cannot be kicked off so baby stays warm and covered throughout their sleep.
  • Longer and more peaceful sleep for both baby and household.
  • No chance for entangled as so often is the case with baby blankets.
  • Replaces loose blankets that can cover a baby’s face and interfere with breathing. Breathing difficulties are one of the causes of SIDS.
  • Reduces the chance of your baby overheating.
  • Eases the transition from swaddling.
  • sleep-sack-in-car-seatMost models are perfect for car seats, strollers, and even on airplanes. No more trying to reach from the driver’s seat to pick up dropped blankets in the back.
  • Perfect for all climates since you decide what your baby wears underneath.
  • Convenient zipper makes diaper changes quick and easy.
  • Makes for a perfect baby shower, birthday, or Christmas gift.
  • Easily machine washable.
  • Putting your baby in a sleeping sack will help them associate it with sleep time making bed time easier.
  • No more feet getting stuck between the rails of a crib.


baby-wearable-blanket-materialSleep sacks come in a variety of materials. Each have their own advantages and the material type should be one of the primary things to decide on when purchasing. While all the below materials are fine choices, they are listed in order of “good” to “best”.

Cotton – Cotton is by far the most widely used material for sleep wear and bedding. It’s very soft, breathable, hypoallergenic, inexpensive, and easy to care for. That said, cotton does wear out a bit quicker than other materials and it can shrink, especially if it’s 100% cotton. Many manufacturers actually use a cotton/polyester blend which provides more durability and less shrinking with little noticeable difference in softness.

Micro-Fleece – Also known as polar fleece, micro-fleece is soft, synthetic wool material created out of polyester. It shares many similarities with wool but it’s lighter, softer, and easily washable. Micro-fleece is also hydrophobic (water-repellent) so if your baby tends to sweat, this might not be the best material for them. Durability is its biggest downfall as it is susceptible to tears and pilling. Because it is synthetic, micro-fleece is fairly inexpensive.

Cotton Muslin – Muslin is a type of finely-woven cotton fabric. It originally came to Europe from the Middle East in the 17th century. The material’s open weave structure makes it lightweight and breathable while still providing warmth and comfort. It’s durable yet has a slight bit of stretchiness to it.

Merino Wool – Merino is considered by many to be the finest natural fiber in the world. Measuring about 1/10th the thickness of a human hair, it contains for spaces for air than synthetic fibers for better insulation. This allows merino wool baby sleeps sacks to be warm, soft, and lightweight. Merino is the material of choice for babies with allergies, sensitive skin, or eczema. This incredible material is also naturally fire-resistant and one of the most durable. A single merino fiber can bend over 20,000 times with breaking meaning they will keep their natural elasticity so garments will keep their original shape after countless washings. Merino has no real downsides except for its premium price.


merino-kids-sleep-sackAs these wearable blankets for babies become more popular, more companies have begun manufacturing their own versions. Listed below are the most popular manufacturers of baby sleep sacks, sleeping bags, and swaddles:

Halo – Halo has been producing sleep sacks and sleep wear for almost 20 years now. The company’s founder and his wife experienced the tragedy of their first born passing away due to SIDS. Because of that, Halo’s mission of “Putting Babies First” was created. The company offers dozens of products from newborn swaddles all the way to wearable blankets in 4-5T size. They have many unique styles and features in a variety of materials. Most of their models can be had for $20-$30 making them the most inexpensive sleep sack producer out there.

Merino Kids – Merino Kids was founded in 2003 by a mother who was researching the availability of sleepwear products for infants, babies, and toddlers. Based out of New Zealand, the company uses 100% natural products such as merino wool and organic cotton in its products. The company has won multiple international design awards and many consider their products. Their products are of the highest quality and considered by many to be the best sleep sacks available although at a premium price. When you take into account that other cheaper brands need to be repurchased every six months in a bigger size and a single Merino Kids sleep sack will last 2 years, the price difference is almost non-existent.

Baby Deedee – Baby Deedee was founded in 2008 by a mom who had the all too common problem of getting her son to sleep at night. Two products, the Baby Deedee Sleep Nest and Sleep Nest Lite, make up most of the company’s product line and they are both top sellers. They are available in a variety of colors and sizes and priced at a mid-way price point.

Woolino – Woolino is another premium manufacturer which uses ONLY natural merino wool in its products. They believe their “4 Season Baby Sleeping Bag” is the absolute best wearable blanket for a child and the many reviews online seem to indicate that it could be true. While you will pay more upfront, you won’t need to get a bigger size every six months like some other brands. A single Woolino sleep sack will last until your baby is two years old.

The Gro Company – The Gro Company is based in the UK where it is most known for its award-winning Grobag baby sleep bag. It is currently the top sleep sack brand in the UK and Australia and is now available for sale in the US. They offer high quality designer sacks at a mid-range price point.

Aden + Anais – Aden + Anais are the baby swaddle specialists. Their extensive use of cotton muslin material is what sets them apart from others. The company was founded in 2006 after a woman moved from her native Australia to the United States and a few years earlier was expecting her first baby. Muslin wraps were commonly used in Australia to swaddle babies but nowhere to be found in the US so she set out to change that. Along with baby swaddles and sleeping bags, Aden + Anais also offers blankets and bib/burp cloths.

Baby in a Bag – Baby in a Bag is company with a tagline of “European Style Baby Sleep Sacks”. After all, that’s where it all started. They produce variety of affordable sleep sacks for infants, babies, and toddlers for all seasons in materials including cotton, silk, and even the super soft Minky fabric.

SwaddleDesigns – SwaddleDesigns was founded in 2002 by a registered nurse who wanted to help parents who struggled with swaddling their newborns and taught them the proper technique. She developed her own swaddling blanket which was highly successful. The company’s product line has since grown to include wearable blankets called zzZipMe Sacks.

Baby Aspen – Baby Aspen designs and produces various boutique-quality baby gifts. They offer a small product line they refer to as “Snuggle Sacks”. What sets them apart is their fun, cute, and whimsy designs that are great for gift giving.

Nini & Pumpkin – Nini & Pumpkin is a recently formed company by two long-time friends who both loved fashion and design and eventually teamed up to form their own business. Nicki (Nini) and Pamela (Pumpkin) launched their first product, the patent-pending Moon Cocoon, and it appears they already have a winner on their hands. We hope to see more products from them in the future.


sleep-sack-sizesEach manufacturer has their own sizing standards. Some, such as Halo, offer up to 6 different sizes ranging from Preemie all the way to 24 months. Others, such as Merino Kids, only have a couple sizes: 0-2 years and 2-4 years. While more sizes generally means a better fit, you will also have to re-buy a sleep sack much sooner in a bigger size. For a lot of people, it simply makes more financial sense to purchase the higher quality and more initially expensive sleep sack since they know it can be used for two full years.

What is TOG?

When looking at various sleep sacks, you will often come across a value labeled TOG. TOG is the unit of measure for thermal insulation most commonly used in textile manufacturing. It is the international standard measurement for how well something keeps you warm. Generally speaking, the higher the TOG value is, the warmer your baby will be. For example, if you live in a warm climate, a sleeping sack with a TOG value of 0.5 would be much more suitable than one with a value of 3.5.

What to Wear Inside a Sleep Sack

what-to-wear-inside-sleep-sackSince a sleep sack is meant to be used as a replacement for a traditional blanket, regular sleepwear should be worn inside it. While some babies naturally sleep warmer than others, the general guideline is that for warmer rooms (68-74 degrees) your baby should wear a short sleeve onsie underneath. For cooler rooms (62-68 degrees), full long sleeve pajamas are most often recommended. If your baby feels sweaty or hot when you touch his neck, they probably need a lighter outfit.

You probably also notice that most variations have no sleeves. While you would think a baby would be cold with their arms uncovered, the truth is that most babies rarely sleep with their arms inside when covered by a traditional blanket. A sleeveless sleep sack helps with air circulation and reduces the chance for overheating. In the colder months, a long sleeve sleep sack, bodysuit, sleepsuit, or pajamas underneath is recommended.

How to Choose the Best Sleep Sack

#1 – Decide on Material

It’s important to first consider the type of material used. Does your little suffer from allergies or have sensitive skin? You may wish to avoid any synthetic materials and go with 100% cotton or merino wool. Do you live in an area that sees warm temperatures year round? You probably don’t want a sleep sack made out of fleece. Cotton may be a better choice.

#2 – Get the Correct Size

It’s extremely important to purchase a size your baby or toddler will fit into now. Your child’s safety is more important than saving a few dollars by purchasing a sleep sack your baby will “grow into”. Pay close attention to the sizing chart each manufacturer has. Getting one that’s too big may result in the baby getting tangled up or slipping down into the sack.

#3 – Get the Most Suitable Weight/Thickness

While there are a couple sleep sacks that claim to be perfect for all seasons, it’s usually best to choose lighter and cooler varieties for the summer months while going with the thicker ones for colder weather. Pay close attention to the TOG value if it is available. It’s a quick at-a-glance way of determining the how warm the particular type is.

#4 – Consider Convenience

Sleeping sacks use various styles of fastening. Most use zippers while others use snaps. As most parents can attest, being able to quickly change a diaper in the middle of the night is very important. This is why a sleep sack needs to be able to allow for quick access. The most valuable models have zippers that open from the bottom up. This allows for super easy diaper changes and keeps the zipper away from the face of a baby. You should also consider how easy it is to wash and dry. One that you can simply toss in the washing machine and dry in the dryer is a great timesaver.