A guide for parents
What should a baby wear to sleep?
Why the chart you're looking for doesn't officially exist, which one to use instead, and the check that beats all of them.
What's in here
- The chart nobody official will give you
- So which chart do you use?
- The bag is fixed. The clothes are the dial.
- The check that beats every chart
- Cooler rather than warmer
- The things that are simply rules
Before anything else: for safer sleep generally, the Lullaby Trust and the NHS are the authorities, not us. This page is about the clothing question specifically, and everything below points back to them.
And that turns out to be the most useful thing on the page.
The chart nobody official will give you
You've searched for a TOG chart. Everybody does. And here is what the UK's leading safer sleep charity says about that.
Which is not them being unhelpful. It's them being precise, and their reasons are worth knowing because they change how you should read every chart you find.
Every product is made of different materials in different proportions, so the amount of heat a bag traps genuinely differs from bag to bag even at the same stated TOG.
And the heat trapped between layers changes things significantly. A sleepsuit under a bag isn't just a sleepsuit, it's a sleepsuit plus the air held between it and the bag.
So a single chart covering every bag and every combination of layers would be wrong for most of them. They decline to publish one because publishing one would be misleading.
So which chart do you use?
The one printed on your own sleeping bag. That's the answer, and it's a genuinely different answer from the one most people act on.
Manufacturers test their own bags in independent labs, for their own fabric and fill, and write their chart from those results. That chart knows something a generic one can't.
A generic chart from the internet
Written for an average bag that nobody owns. Useful as a rough sense of the direction.
The chart on your bag's label
Tested for that exact fabric and fill. Where the two disagree, this one wins.
Keep the packaging, or photograph the chart before you throw it away. It's the single most useful thing in the box.
The bag is fixed. The clothes are the dial.
Here's the practical way to think about it, and it makes the whole thing much simpler.
You own the bag you own. Most families have one or two and aren't buying a new TOG every time the weather turns. So the bag is a constant, the room temperature is whatever it is tonight, and the only thing you actually adjust is what they're wearing underneath.
So rather than a chart that tries to cover every bag, here's what to put on them for the bag you've already got.
Before the table
This is the general UK convention and a starting point, not gospel. The chart on your own bag wins where it differs, because it's tested for that fabric. And whatever the table says, the real check is their chest or the back of their neck.
The NHS and the Lullaby Trust both give 16 to 20°C for baby sleep, all year round.
Find the temperature, read across to the bag you own.
| Room | 2.5 TOG bag | 1.0 TOG bag | Blankets, no bag |
|---|---|---|---|
| 16°C | Long-sleeved vest and a sleepsuit | Too light. Add a layer or use the warmer bag. | Vest, sleepsuit, two light blankets |
| 17-18°C | Short-sleeved vest and a sleepsuit | Vest and a sleepsuit | Vest, sleepsuit, two light blankets |
| 19-20°C | A sleepsuit on its own | Short-sleeved vest and a sleepsuit | Vest, sleepsuit, one light blanket |
| 21-22°C | Short-sleeved vest only | A sleepsuit, or a vest on its own | Short-sleeved vest and a sheet |
| 23-24°C | Too warm. Switch to the lighter bag. | Short-sleeved vest only | Short-sleeved vest, nothing over |
| 25°C+ | Too warm. | Just a nappy, or no bag at all | Just a nappy, nothing over |
Blankets go no higher than the shoulders, tucked in, feet at the bottom of the cot. A blanket folded double counts as two, which is the easiest way to add far more warmth than you meant to.
The rule of thumb if you'd rather not read a table
Roughly what you'd be comfortable in, plus one light layer. If you're in pyjamas under a duvet, they can be in a sleepsuit and a bag. If you're in something lighter, a vest and a bag.
And measure the room rather than guessing it. A thermometer at cot level is a few pounds and it removes the guesswork from the one number the whole table depends on. Adults are unreliable thermometers, and heat pools unevenly, so the reading by the door is not the reading in the cot.
Most families find a 1.0 and a 2.5 cover the whole British year between them. You don't need one of every rating whatever the shop suggests.
The check that beats every chart
No table survives contact with your actual baby in your actual room. The table gets you close; this tells you whether you got there.
Feel their chest, or the back of their neck
Warm and dry is right. Clammy or damp means too warm, and it's time to take a layer off.
Not their hands or feet
Cool hands and feet are completely normal in a baby who's perfectly warm. This is the most common false alarm there is.
Worth doing on the first night with any new bag, and on any night the weather has turned. After a while you'll stop needing to.
Cooler rather than warmer
If you're between two answers, or between two TOGs, go lighter. And the reason is worth stating plainly, because it's the thing that actually settles the decision at eleven at night.
If they're too warm
Overheating is associated with an increased risk of sudden infant death, and a sleeping baby can't do anything about it.
If they're a bit cold
They wake up and tell you. Loudly. And you add a layer.
The two outcomes are not equivalent, which is why erring cool is the safer direction rather than just a preference. In a warm room a short-sleeved vest, or nothing but a nappy, is genuinely fine.
The things that are simply rules
| Rule | Why |
|---|---|
| No hats indoors for sleep | Babies release heat through their heads, and covering it raises the risk of overheating |
| No blankets on top of a sleeping bag | Add a layer underneath or use a higher TOG instead |
| One blanket doubled over counts as two | It is easy to add far more warmth than you intended |
| Nothing loose in the cot | No duvets, quilts or pillows under twelve months |
| No weighted sleeping bags | The Lullaby Trust advise against them |
| Blankets no higher than the shoulders | Tucked in, feet at the bottom of the cot |
All of that is Lullaby Trust guidance rather than ours, and their site is where to read it properly.
I spent months cross-referencing charts online and then found out the chart on the bag was the one that counted all along. It was on the label the whole time.
🌱 While you're here
Sleeping bags are outgrown in about six months and cost £25 to £40 each. You need two TOGs, and then you need them all again a size up.
Swapaboo is a clothes swap. What they've grown out of pays for their next size, so the clothes themselves cost you nothing. You just pay to have them moved.
Everything's checked and graded before it lists, sleeping bags included, and the TOG is listed so you know what you're claiming.
We're opening a few families at a time. Pop your email in and we'll let you know when there's a place.
Common questions
What should a baby wear to sleep?
It depends on the room temperature and the TOG of the sleeping bag. A common approach is a vest alone in a warmer room, or a vest and a sleepsuit in a cooler one, under a bag chosen for that temperature. The NHS and the Lullaby Trust recommend a room temperature of 16 to 20 degrees. Check the chart printed on your own sleeping bag, since it is written for that specific product.
Is there an official TOG chart from the Lullaby Trust?
No. The Lullaby Trust states that it cannot provide a chart matching room temperature to clothing layers and TOG, because every product uses different materials in different proportions, the thermal insulation varies between products, and the heat trapped between layers changes the warmth significantly. They advise following the guidance supplied with the specific sleeping bag being used.
What TOG sleeping bag does my baby need?
Most families find that a 1.0 TOG and a 2.5 TOG cover the whole UK year, with the clothing worn underneath making the finer adjustment. The chart supplied with your particular bag is the one to follow, since manufacturers test their own products and write their guidance for that fabric and fill.
How do I know if my baby is too hot at night?
Feel their chest or the back of their neck. Warm and dry is right, while clammy or sweaty means they are too warm and a layer should come off. Hands and feet are not a reliable guide, as it is normal for a comfortable baby to have cool hands and feet.
Should I dress my baby warmer or cooler for sleep?
Cooler, if you are unsure. Overheating is associated with an increased risk of sudden infant death, whereas a baby who is slightly cold will usually wake and let you know. If you are between two TOG ratings, the lighter one with an extra layer underneath is the safer choice.
Can a baby wear a hat to sleep?
Not indoors. Babies release excess heat through their heads, so covering the head during sleep increases the risk of overheating. Hats are for outdoors only.