Baby Sleep Sack TOG Chart by Room Temperature

Which TOG sleep sack for which room, and what to wear under it, from 16–26°C (61–79°F). The Baby Layers app's own table, with the safe-sleep basics.

Which sleep sack for which room, and what goes under it, in °C or °F. The same table the Baby Layers app uses, for babies up to a year.

Match the sack to the room, not the season. Brands vary a little, so your sack's own label wins over this table.

26°C (79°F) and up: No sack, short-sleeve bodysuit. 24–25°C (75–77°F): 0.5 TOG, short-sleeve bodysuit. 21–23°C (70–73°F): 1.0 TOG, short-sleeve bodysuit. 18–20°C (64–68°F): 2.5 TOG, long-sleeve bodysuit. Under 18°C (64°F): 2.5 TOG, long-sleeve bodysuit and sleepsuit.

In between

Sacks are sold in other ratings too. The app still names one of the three above, and shows these as working too for a room of:

19–21°C: 1.5 TOG, between 1.0 and 2.5. 18–20°C: 2.0 TOG, between 1.0 and 2.5.

Another number on the label, like 0.2 or 1.2? Go by the nearest row, and pick the lighter sack if unsure.

The safe-sleep charities point to the sack makers' own charts for the TOG per room. Those charts give roughly: no sack from about 27°C, 0.5 TOG for 24–26°C, 1.0 TOG for 21–23°C, 2.5 TOG for 16–20°C, and 3.5 TOG below 16°C.

Baby Layers follows them with two differences, both on the cooler side. From 26°C it suggests no sack at all, a step lighter than the charts. And in a room below 18°C it adds a sleepsuit under the 2.5 TOG sack rather than moving to a warmer sack. The Lullaby Trust says a cooler room can take an extra layer of clothing or a warmer sleeping bag, and the app takes the layer.

Nothing, not the baby's age and not a parent's setting, ever makes the app's sack warmer than the chart. A baby is safer slightly cool than too warm.

TOG is a warmth rating: how much warmth a sleep sack or blanket holds in. The higher the number, the warmer. A warmer room calls for a lower TOG, a cooler room for a higher one.

The chart is the same from birth to a year. For sleep, the app never dresses a newborn warmer than the chart, even though it does outside.

Toddlers run warm, so the app dresses a 1–3 year old a touch lighter, as if the room were a little warmer.

A swaddled newborn wears the swaddle in the sack's place. Swaddling stops at the first signs of rolling, around three months.

No hats or loose blankets for sleep. Check the neck — warm but not sweaty means just right.

Sources

Sleep, by room temperature

What TOG sleep sack for a room of 20°C?

A 2.5 TOG sack over a long-sleeve bodysuit is the usual starting point for a room of 18–20°C, which is inside the 16–20°C the Lullaby Trust recommends for a baby's room.

What TOG for a warm room?

For a room of 21–23°C, a 1.0 TOG sack over a short-sleeve bodysuit. For 24–25°C, a 0.5 TOG sack. From 26°C, Baby Layers suggests a short-sleeve bodysuit and no sack.

What if the room is cooler than the chart?

Below 18°C, Baby Layers adds a sleepsuit under the 2.5 TOG sack, over a long-sleeve bodysuit. The makers' charts move to a 3.5 TOG sack below 16°C. Whichever you use, follow the chart on your own sack's label and never add a blanket on top.

Can a baby wear a hat to sleep?

No. Never a hat for sleep, whatever the room. A baby cools down through the head, and the head and face stay uncovered.

How do I know if the TOG is right?

Once your baby is settled, check the chest or the back of the neck. Warm but not sweaty is just right. Cool hands and feet are normal. A sweaty neck or a hot tummy usually means one layer less.