TOG stands for thermal overall grade and measures how warm a sleeping bag is. The higher the TOG, the warmer the bag. Choosing the right one comes down to a single number: the temperature of the room your baby sleeps in, measured with a thermometer rather than guessed. This guide covers every TOG we make, what your baby should wear underneath, and how a sleeping bag should fit.
Baby sleeping bag TOG chart
| Room temperature | TOG to use | What baby wears underneath |
|---|---|---|
| Over 24°C | 0.5 TOG | Short sleeve bodysuit, or nappy only on very hot nights |
| 21 to 24°C | 1.0 TOG | Short sleeve bodysuit or light sleepsuit |
| 18 to 21°C | 1.5 TOG | Short or long sleeve bodysuit under a sleepsuit |
| 16 to 20°C | 2.5 TOG | Long sleeve bodysuit under a sleepsuit |
| Under 16°C | 3.5 TOG | Long sleeve bodysuit under a sleepsuit |
The NHS recommends a room temperature of 16 to 20°C for baby sleep, which is why the 2.5 TOG is the most used bag in UK homes. Most families find a 1.0 TOG and a 2.5 TOG cover the whole year between them.
0.5 TOG: hot summer nights
For rooms above 24°C, heatwaves and warm holidays. The lightest layer we make, in breathable 95% organic bamboo that moves heat away rather than trapping it. On the hottest nights a nappy and the bag alone is enough. Shop the 0.5 TOG sleeping bag.
1.0 TOG: typical UK summer
For rooms between 21 and 24°C, which is most UK bedrooms from late spring to early autumn. Pair with a short sleeve bodysuit, or a light sleepsuit at the cooler end. Shop the 1.0 TOG sleeping bag.
1.5 TOG: spring and autumn
The in-between bag for rooms of 18 to 21°C, when a 1.0 feels light but a 2.5 feels too much. If your nursery swings between seasons, the 1.5 TOG bridges the gap. Shop the 1.5 TOG sleeping bag.
2.5 TOG: the year-round UK standard
For rooms of 16 to 20°C, the range the NHS recommends for baby sleep. This is the bag most parents use for most of the year, over a long sleeve bodysuit and sleepsuit in winter or lighter layers in milder weeks. Shop the 2.5 TOG sleeping bag.
3.5 TOG: cold rooms and winter
For rooms that sit below 16°C, such as older houses in deep winter. Layer a long sleeve bodysuit and sleepsuit underneath, and never add a blanket on top of a sleeping bag at any TOG. Shop the 3.5 TOG sleeping bag.
How a sleeping bag should fit
Fit matters as much as TOG. The neck opening should sit snugly so your baby cannot slip down inside the bag, and the armholes should be close without restricting movement. With the zip closed, you should not be able to pull the bag over your baby's head. Our bags come in three sizes: 0-9 months, 9-18 months and 18-36 months, each sized by height rather than age, with the exact measurements on every product page.
Why a sleeping bag rather than a blanket?
The NHS and The Lullaby Trust both recommend baby sleeping bags over loose blankets, because a bag cannot be kicked off or ride up over the face, and it keeps your baby at a steady temperature however much they wriggle. Our QikZip two-way zip opens from the bottom, so night nappy changes happen without taking the bag off or fully waking your baby.
How to check your baby is the right temperature
Feel the chest or the back of the neck, not the hands or feet, which naturally run cooler. Warm and dry is right. Hot, damp or clammy means remove a layer; if in doubt, a room thermometer settles it. Signs of overheating include flushed cheeks and rapid breathing.
Shop the range
Every BABYGO sleeping bag comes in 0.5, 1.0, 1.5, 2.5 and 3.5 TOG with the two-way QikZip and soft 95% organic bamboo. Browse all baby sleeping bags, pair one with a bamboo zip sleepsuit for the layers underneath, or get both together in the Sleepsuit and Sleeping Bag set.