Sleep Bag TOG Guide
Quick answer
A sleeping bag's TOG rating indicates how warm it is and can help you choose suitable sleepwear for your baby's room temperature. This guide explains common TOG ratings, what your baby can wear underneath and how to reduce the risk of overheating.
I genuinely thought TOG charts were way more complicated than they actually are.
Once you strip away all the charts and different brands, it mostly comes down to:
your room temperature
whether your baby naturally runs warm or cool
not layering loads “just in case”
Sleep bags are one of those things that sound simple until you actually start shopping for baby stuff and realise there are 400 versions, different TOGs, swaddles, transition bags, and everyone online saying something different.
It’s very similar to figuring out what you actually need before baby arrives, which I talked about more in my Preparing for a Baby guide too.
Cooler rooms (under 18°C)
This is probably the part most people overthink.
If the room feels genuinely cold, layering underneath the sleep bag usually makes more sense than immediately buying the thickest TOG possible.
For a lot of babies, something like:
long-sleeve vest
sleepsuit
2.5 TOG bag
is already completely enough.
I think people sometimes assume colder room = loads more layers, but overheating can happen surprisingly easily too.
The biggest thing that helped me was realising the charts are more of a starting point than an exact science.
And honestly, babies are all slightly different with this stuff anyway. Some naturally run warmer than others.
A warm chest or back usually matters more than cold hands or feet, because those are often cool anyway.
Average to warmer rooms (18–22°C+)
Once rooms get warmer, it usually becomes more about not overheating them.
A lot of babies are completely comfortable in:
a short-sleeve vest + lighter TOG
or even:just a sleepsuit + lighter bag
depending on the temperature.
This was another thing I overcomplicated at first because online charts make it feel like there’s one perfect setup you’re supposed to follow.
Realistically, most people end up adjusting slightly based on:
their house temperature
the season
whether baby naturally runs warm or cool
It’s honestly similar to feeding in that way too. The recommendations help, but real life usually looks slightly different depending on your baby. I talked about that a bit more in my Newborn Feeding Explained Simply guide.
You also don’t need extra blankets over the top of a sleep bag. The sleep bag is supposed to replace loose bedding rather than add to it.
What helps: Products I actually used
Room Thermometer.A room thermometer also helps way more than I expected, especially when the weather randomly changes overnight and the bedroom suddenly feels completely different.
Sleeping Bag. A double-zip sleeping bag genuinely makes middle-of-the-night changes less annoying because you can unzip from the bottom instead of taking the whole thing off.
Swaddle Up or Traditional Swaddle. If your baby keeps startling themselves awake, some babies settle really well in traditional arms-down swaddles, while others prefer the arms-up styles where they can keep their hands near their face.
The different types explained simply
This was the part that confused me the most at first because every brand seems to invent their own version.
Swaddle wraps
Mostly used during the newborn stage to help with the startle reflex by keeping arms tucked in.
Arms-up swaddles
Same idea, except baby keeps their hands up near their face. Some babies settle way better like this.
Transition bags
Usually used once baby starts showing signs of rolling. They let you gradually move from swaddling to arms-out sleeping.
Standard sleep bags
The most common option once swaddling is finished.
Sleeping bags with legs
Usually more useful once babies get older and start standing or walking around.
The main thing worth remembering is that swaddling should stop once baby starts showing signs of rolling.
Final thought
I think TOG charts are helpful, but people online sometimes make them sound much scarier than they actually are.
After a while, you stop focusing so much on the exact number and just get better at noticing what your own baby is comfortable in.
This isn’t professional advice — just a simple breakdown of what I’ve found helpful.
Most of this is easier to understand visually.
I’ve put all my guides into one place so you can browse them properly.
FAQs
What TOG should my baby wear at night?
It mostly depends on the room temperature rather than the season itself. A lot of parents end up checking the room thermometer more than the weather app because bedrooms can change temperature really quickly overnight.
How do I know if my baby is too hot in a sleep bag?
A sweaty neck, damp chest, or flushed skin usually means baby is too warm. Cool hands and feet are actually really common and don’t automatically mean they’re cold.
Do babies wear clothes underneath sleep bags?
Yes — the sleep bag replaces blankets, not clothing completely. Most babies still wear a vest, sleepsuit, or both underneath depending on the room temperature and TOG.
Are arms-up swaddles better than traditional swaddles?
Honestly, it depends on the baby. Some settle much better with arms tucked down, while others naturally like sleeping with their hands up near their face and sleep better in arms-up styles.
When should I stop swaddling my baby?
Swaddling should stop once your baby starts showing signs of rolling. That’s usually when people move to transition bags or standard arms-out sleep bags instead.
Explore more guides