TOG stands for Thermal Overall Grade — a unit that measures how warm a fabric is. The higher the TOG number, the more insulating the sleep sack. A 0.5 TOG sack is lightweight and best for warm rooms, while a 2.5 or 3.5 TOG sack is designed for cooler nurseries. Choosing the right TOG for your room temperature is one of the simplest ways to keep your baby comfortable and safe through the night.
TOG ratings were originally developed for adult bedding and have been adapted by baby sleep brands like HALO, Ergobaby, Love To Dream, Kyte Baby, Woolino, Slumbersac, Molis&co and Tommee Tippee. While exact temperature recommendations vary slightly between brands, the underlying principle is the same: match the TOG of the sack to the ambient room temperature, then adjust clothing layers underneath.
Common TOG ratings at a glance
- 0.2–0.5 TOG — very light, ideal for warm rooms (24°C+ / 75°F+).
- 1.0 TOG — light, for rooms around 21–23°C (70–73°F).
- 2.5 TOG — standard year-round for rooms 16–20°C (61–68°F).
- 3.5 TOG — extra warm for cold rooms below 16°C (61°F).