Tog Rating Sleep Sacks | Pick The Right Warmth

A TOG rating measures a sleep sack’s warmth, and matching it to your nursery’s temperature keeps your baby comfortable and safe all night.

Figuring out how to dress a baby for sleep is stressful, and the TOG rating on sleep sacks is the tool that removes the guesswork. TOG stands for “Thermal Overall Grade,” a standard textile measurement of how much warmth a fabric provides. In practice, the number tells you how insulating the sack is and, paired with your room’s temperature, which one to buy and how to layer underneath.

What Do The TOG Numbers Actually Mean?

Sleep sacks generally fall into a TOG range of about 0.2 to 3.5. The lower the number, the thinner and cooler the sack; the higher the number, the warmer and more insulated it is. A 0.2 TOG sack is a light muslin layer for hot summer nights, while a 3.5 TOG sack is a padded, fleece-lined option for a cold room.

Manufacturers design their temperature charts around this scale, and while the ranges vary slightly by brand, the core logic is constant. Health experts at Cleveland Clinic note that these charts are a guide, and the American Academy of Pediatrics does not publish specific TOG recommendations. You’re choosing within a safe framework rather than a strict medical rule.

Matching TOG To Room Temperature

The single most important rule is to pick the sack based on the temperature of the nursery, not the season or how cold you feel. A warm house in winter means a lighter sack than a drafty room in summer. Here’s a condensed version of the typical manufacturer guidance:

Look at the temperature bands where brands like Love to Dream and Halo overlap — they’re consistent on the core numbers, which gives you a reliable benchmark even if one chart says 1.0 TOG and another says 1.5 TOG for the same room.

Safety Rules: Overheating And Layering

Overheating is the main risk with sleep sacks, not chilling. Cleveland Clinic warns that a TOG rating of 4.0 is too hot for safe sleep, and Halo advises that no baby should use anything above 4 TOG. In a warm room, a high-TOG sack traps dangerous amounts of heat.

The other common mistake is layering too heavily underneath. The TOG chart assumes a base layer of standard cotton pajamas — when you add blankets, hats, or thick fleece sleepers under a high-TOG sack, you’re stacking insulation the chart didn’t account for. If you’re using a 2.5 TOG sack in a 64°F room, a long-sleeve cotton onesie is all the base layer you need.

Always check the back of the baby’s neck, not their hands or feet, to judge if they’re too warm. Damp or sweaty skin there means they’re overheated — remove a layer or swap to a lower TOG sack.

Putting TOG To Work At Bedtime

Check the room temperature with a standalone thermometer, since thermostats don’t always reflect the crib’s corner of the room. Then pick the sleep sack that fits the band and dress the baby in the matching base layer. When the room sits between two charts, go with the lower TOG option and add a layer of clothing rather than risking an overheated night.

If you’re weighing which sack to buy for your nursery’s climate, our tested roundup of the best baby sleep sacks this year breaks down the options by warmth and fit.