Sleep-Sack TOG Calculator
Enter the nursery temperature you measured for the TOG band most sack labels give and one light layer underneath. The chart on your sack’s label decides.
The sack's label decides, the room comes first
A sleep sack is a wearable blanket: the AAP’s alternative to loose bedding. Its TOG rating is the maker’s label, and so is the room chart that goes with it. Use a room thermometer, keep the room within 16–20°C where you can, keep the under-layer light, and never add a blanket, a hat or a weighted product.
Check the room itself with the Baby Room Temperature Guide, and dress for daytime cold outdoors with the Baby Layering Guide.
Frequently Asked Questions
What TOG sleep sack should my baby wear?
TOG is the sack maker's own rating, and the chart on your sack's label decides. As a typical band: 0.5 TOG from 24 °C, 1.0 TOG from 20 °C, 2.5 TOG from 16 °C. At a boundary this tool takes the lighter band. Below 16 °C it gives no figure.
What should my baby wear under a sleep sack?
One light layer, set by the room: a nappy only from 27 °C, a short-sleeve bodysuit from 20 °C, a long-sleeve bodysuit from 16 °C. The tool never stacks clothing layers under the sack. Follow your sack's label where it differs.
What if the room is colder than 16 °C?
Warm the room toward the 16-20 °C range The Lullaby Trust recommends. Do not add layers, a warmer sack or a blanket: the AAP lists blankets among the loose bedding that can increase the risk of suffocation, and says "Don't use weighted blankets, sleepers, swaddles or other weighted objects on or near your baby."
Is this medical advice?
No. It reports a typical label band for the temperature you enter and quotes the AAP and The Lullaby Trust. Sacks vary by brand, so the label decides. Judge warmth at the chest or the back of the neck.
Informational only: a typical label band for the temperature you enter, not medical advice. Follow your sack’s label and current safe sleep guidance, and consult your pediatrician with any concern.