In short: the TOG rating tells you how warm a sleeping bag is. For the recommended nursery temperature of 16–20 °C, the most common choice is TOG 2.5; at 21–23 °C choose TOG 1.0, in summer above 24 °C TOG 0.5, and below 16 °C TOG 3.0–3.5. Adjust the clothes underneath to the temperature and always check your baby's warmth on the back of the neck or the chest.
Author: Eva Birsa, mum and co-founder of Evitas · Updated: 27 Sep 2026
What is a TOG rating?
TOG (Thermal Overall Grade) is a measure of a fabric's thermal insulation. The higher the TOG, the warmer the sleeping bag. Baby sleeping bags usually come in 0.5, 1.0, 2.0–2.5 and 3.0–3.5 TOG.
But TOG isn't everything: how warm your baby feels also depends on the fabric (cotton, muslin, wool), what they wear underneath and the room temperature. That's why you should always use the TOG rating together with a room thermometer.
TOG chart: which sleeping bag to choose for your room temperature
| Room temperature | Recommended TOG | What to wear under the sleeping bag |
|---|---|---|
| above 27 °C | TOG 0.5 or no sleeping bag | nappy only or a short-sleeved bodysuit |
| 24–27 °C | TOG 0.5 | short-sleeved bodysuit |
| 21–23 °C | TOG 1.0 | long-sleeved bodysuit |
| 18–20 °C | TOG 2.5 | long-sleeved bodysuit |
| 16–17 °C | TOG 2.5 | long-sleeved bodysuit + sleepsuit |
| below 16 °C | TOG 3.0–3.5 | long-sleeved bodysuit + sleepsuit |
The chart is a guide. Every baby is different and every manufacturer measures TOG slightly differently, so also follow the sleeping bag manufacturer's instructions.
Which TOG to choose for each season?
- Summer (TOG 0.5): thin, breathable muslin or cotton bags, e.g. Jollein muslin sleeping bags or summer Little Dutch sleeping bags.
- Spring and early autumn (TOG 1.0): for warmer bedrooms, e.g. Done by Deer TOG 1.0 sleeping bags.
- Autumn and winter in a heated home (TOG 2.0–2.5): the most versatile choice for most homes, e.g. Done by Deer TOG 2.5 or the Little Dutch TOG 2.0 winter sleeping bag.
- Cold bedrooms (TOG 3.0–3.5): e.g. Jollein sleeping bags with removable sleeves that you can adapt once the room warms up.
If you're buying just one sleeping bag for the whole year, TOG 2.5 covers most needs in a heated home; in summer, swap it for a TOG 0.5.
Which sleeping bag size should you choose?
| Bag length | Approximate age |
|---|---|
| 60–70 cm | 0–6 months |
| 90 cm | 6–18 months |
| 110 cm | 18–36 months |
The most important thing is the fit around the neck and shoulders: the neck opening must not be so big that your baby can slip down inside the bag. At the bottom, the bag should leave enough room for kicking and healthy hip development. If you're between two sizes, check the manufacturer's weight and height chart.
Why is a sleeping bag safer than a blanket?
- Your baby can't pull it over their face, which with a blanket is one of the risk factors for sudden infant death syndrome (SIDS).
- It can't be kicked off at night, so the temperature stays even and your baby wakes less.
- It lets the legs move freely while keeping the body warm.
- It becomes part of the bedtime routine, signalling to your baby that it's time to sleep.
Safe sleep in a sleeping bag: 7 rules
- Keep the room temperature between 16 and 20 °C.
- Check warmth on the back of the neck or the chest, not on the hands and feet, which are usually cooler.
- If the skin is hot or sweaty, remove a layer of clothing or choose a lower TOG.
- A baby in a sleeping bag doesn't need an extra blanket. Don't combine two sleeping bags, or a sleeping bag and a blanket.
- Indoors, don't put a hat on your baby for sleep and don't use sleeping bags with hoods.
- Weighted sleeping bags and blankets are not recommended for babies under 1 year.
- Always put your baby to sleep on their back, on a firm, flat surface without pillows or toys.
Frequently asked questions
What TOG does a baby need in winter?
In a heated home at 16–20 °C, the most common choice is TOG 2.5 with a long-sleeved bodysuit. Choose TOG 3.0–3.5 only if the room is below 16 °C.
From what age can a baby sleep in a sleeping bag?
From birth, as long as the sleeping bag fits well around the neck and shoulders. For newborns, choose the smallest size (60–70 cm).
How do I know if my baby is too hot in a sleeping bag?
Feel the back of their neck or their chest. If the skin is hot, sweaty or flushed, your baby is too hot. Cool hands and feet are normal and don't mean your baby is cold.
Does a baby in a sleeping bag also need a blanket?
No. The sleeping bag replaces the blanket. An extra blanket increases the risk of overheating and of the face being covered.
Are removable sleeves useful?
Yes, especially in between seasons. With sleeves the bag is warmer; without them you can keep using it when the room warms up.
Can I use a sleeping bag in a car seat?
Regular sleeping bags are not suitable for a car seat, because a thick layer under the harness reduces protection. In the car, dress your baby in thin layers and put a blanket over the fastened harness.
Choose a sleeping bag for your baby
At Evitas you'll find baby sleeping bags in every TOG rating and size from Jollein, Done by Deer and Little Dutch. Browse the full range in our baby sleeping bags category.
Read also: Jollein sleeping bags – safety and comfort for your baby.
Sources
- The Lullaby Trust – How to dress your baby for sleep
- The Lullaby Trust – Cold weather
- The Lullaby Trust – Hot weather
This content is for information only and does not replace advice from your paediatrician or health visitor.
