Quick answer

Choose a TOG rating based on your baby's room temperature. Use TOG 0.5 for warm rooms (24°C+), TOG 1.0 for moderate rooms (20-24°C), and TOG 1.5 for cooler rooms (16-20°C). Always pair the sleep sack with appropriate clothing and check your baby's neck or chest for warmth.

What does TOG rating mean for baby sleep sacks?

TOG stands for Thermal Overall Grade and measures how well a fabric insulates. A higher TOG means more warmth. For baby sleep sacks, TOG ratings typically range from 0.5 (lightweight) to 2.5 (heavy). The right choice keeps your baby comfortable without overheating, which is linked to safer sleep. Room temperature is the primary factor, but your baby's age, activity level, and the sleep sack's fabric also matter.

How room temperature guides your TOG choice

The safest room temperature for baby sleep is between 16°C and 24°C. Use a reliable room thermometer near the crib, away from windows or heaters. For rooms above 24°C, choose a TOG 0.5 sleep sack, which is the lightest option. For 20-24°C, a TOG 1.0 works well. For 16-20°C, go with TOG 1.5. Avoid using extra blankets or layers on top of the sleep sack, as they can cause overheating.

Fabric matters: cotton vs. fleece vs. micro-fleece

Cotton sleep sacks, like the HALO SleepSack https://halosleepus.com/products/swaddle-100-cotton-tog-1-5-80921https://halosleepus.com/products/swaddle-100-cotton-tog-1-5-80923https://halosleepus.com/products/swaddle-100-cotton-tog-1-5-80927https://halosleepus.com/products/swaddle-100-cotton-tog-1-5-80937Swaddle 100% Cotton TOG 1.5, are breathable and ideal for year-round use in moderate climates. Micro-fleece, such as the HALO SleepSack Wearable Blanket Disney Winnie the Pooh TOG 1.0, is soft and cozy but less breathable, making it better for cooler rooms. Always check the TOG rating on the product label—fabric alone doesn't tell you the warmth. For warm weather, cotton TOG 0.5 sleep sacks are a great choice.

How to choose the right TOG rating in 4 steps

  1. Measure the room temperature: Place a digital thermometer in the nursery, away from direct heat or drafts. Check the temperature before every sleep period. Write it down or use a baby monitor with a temperature sensor. Common mistake: relying on your own comfort. Babies regulate temperature differently. Always use a thermometer.
  2. Match TOG rating to temperature range: Use this quick guide: TOG 0.5 for rooms above 24°C, TOG 1.0 for 20-24°C, TOG 1.5 for 16-20°C. For rooms below 16°C, consider a TOG 2.5 sleep sack or adjust the room temperature instead. Checkpoint: If the room is 22°C, choose TOG 1.0. Don't guess—refer to the chart on the product page.
  3. Dress your baby appropriately underneath: For TOG 0.5, use a short-sleeve onesie or just a diaper. For TOG 1.0, a long-sleeve onesie or lightweight pajamas. For TOG 1.5, footed pajamas or a long-sleeve bodysuit. Avoid hats or extra blankets inside the sleep sack. Common mistake: overdressing under a sleep sack. Check your baby's neck or chest—it should feel warm, not hot or sweaty.
  4. Check your baby's temperature during sleep: After 30 minutes of sleep, feel your baby's chest or the back of the neck. If it's hot or sweaty, remove a layer or switch to a lower TOG. If it's cool, add a layer or use a higher TOG next time. Never use a blanket or duvet. Final verdict: Your baby's comfort is the ultimate guide. Adjust based on how they feel, not just the thermometer.

Sleep sacks that fit different TOG needs

  • Toddler 100% Cotton TOG 0.5: Give your toddler the comfort of a familiar bedtime routine with the HALO SleepSack Toddler, now designed for their growing independence. Toddler combines their beloved SleepSack with the freedom to move around as they walk and explore. With several adjustable features, it adapts to your child’s growth over a full year. The 12-month and 2T sizes offer convenient zippers for easy diaper changes, while the 3T size has… The TOG 0.5 rating makes this a great choice for warm rooms or summer sleep. The adjustable features also help the sack fit longer, so you don't need to size up as often.
  • Swaddle 100% Cotton TOG 1.5: Our best-selling, award-winning SleepSack® Swaddle features a versatile 3-in-1 design (arms in, hands to face, or out!) that caters to your baby’s sleep preferences for a better night of rest. Adjustable wings make swaddling easy and the double zipper makes midnight diaper changes simple and quick. The roomy design supports healthy hip development and allows for comfortable movement while preventing the Moro reflex… With a TOG 1.5 rating, this swaddle is ideal for cooler rooms (16-20°C). The 3-in-1 design lets you adjust arm coverage as your baby's sleep habits change, and the double zipper makes nighttime changes faster.
  • Disney™ Winnie the Pooh Wearable Blanket Micro-Fleece TOG 1.0: HALO® meets Disney’s Hundred Acre Wood with our SleepSack® wearable blanket featuring beloved Disney Winnie the Pooh characters. An ideal next step after SleepSack Swaddle for safe, comfortable sleep. Design details include a zipper that opens from the bottom for easy diaper changes, and a roomy, extra long sack. It’s hip healthy and you won’t have to size up as fast. Soft micro-fleece is breathable, cozy and gentle… The TOG 1.0 rating suits moderate room temperatures (20-24°C). The micro-fleece fabric is soft and cozy, and the extra-long sack means it lasts longer before you need to size up. The bottom zipper is convenient for diaper changes without fully waking your baby.