Have you heard of a sleep sack (also known as a sleep bag)?  I talk about them often, for good reason. If you have not, you might read a little further because a sleep sack can be a fantastic sleep tool for both your baby and your toddler.

Infant safety

Until a baby reaches 12 months of age we want to be diligent in keeping our baby safe in the crib. It can be very tempting to wrap a blanket around your baby to help keep them warm, especially in the winter months.  However, anything loose in an infant’s crib is a safety hazard.  An appropriately sized sleep sack is a safe and wearable blanket. Knowing that your little one is cosy in their crib with a blanket that will not come off, now that will give you peace of mind.

It is important to keep in mind that we want to keep our babies on the cooler side for sleep.  A sleeping temperature of somewhere between 68 – 72 degrees is not only ideal, but important for safety.

Avoid the crib to bed transition too soon

When our kids get to that age when they start to climb out of the crib (usually around 18 months), a sleep sack is one way to help prevent it.  It can help to prevent them from being able to throw their leg over the rails of the crib.

If you can get your child used to a sleep sack at an early age, when you get to the 18 month mark, they will already be very comfortable with it.  However, it was not something you introduced early on, don’t fret.  Your child can still grow to love their sleep sack.


Putting your child into a cozy sleep sack as part of your bedtime routine is very helpful communication to your child that sleep is coming.  We communicate with our kids in multiple ways before language comes into play.  One of those ways is being predictable.  If you put it on for every nap and bedtime it will send cues to your child’s body that it is time to sleep.

What to look for in a sleep sack


A sleep sack should look like an A-Frame dress.  It should be loosely fitted around the body and feet and more fitted (for safety) around the neck and arms.

Appropriate sizing

Sizing is measured by age and weight.  Be sure to pick one that is a proper fit for your child. For safety, you want to make sure that the neck and arm fitting are fitted enough so that your baby cannot pull the sleep sack over their face.


Sleep sacks can be long in length in the foot area, and that is ok.  This can come in handy to ensure that your child can move around well in the crib and when they get a bit older, they can walk around.


Look for a sleep sack in a soft and breathable fabric.  I love jersey cotton.  When looking at sleep sack I think about if I would want to sleep in it.  Would it be comfortable for me?  Breathable is also important because you want to help keep your child from overheating.


Sleep sacks also come in “togs.”  A tog measures the thermal insulation of the sleep sack.  A 1 tog sleep sack is about the weight of a layer or two of jersey cotton and is great for the summer months. A 2.5 tog sleep sack is quite a bit heavier and more appropriate for the winter months in colder climates.

When should a child stop sleeping in a sleep sack?

I am asked this question often.  This is because children learn to LOVE their sleep sacks.  I recommend a sleep sack for as long as they are in a crib, and ideally, that is until they are 2.5-3 years of age.  However, if your child moves into a big kid bed and wants to keep their sleep sack, what’s the harm? If it helps the move to the big kid bed go more smoothly, then we’ll take that, right?  Companies like Little Fishkopp (shown in the images) make longer sleep sacks, that my 3 year old still fits into.  We (the boys and I) LOVE the Little Fishkopp sleep sacks.

All in all, a sleep sack is an excellent sleep tool.  Introduce it at anytime from the transition from a swaddle to the toddler climbing out of the crib stage, but the earlier the better.  A sleep sack will become a loved part of the bedtime routine in your home soon too.

My Best,





Certified Sleep Consultant

Good Night Sleep Site Florida