Sleep Sack TOG Chart: What to Wear Under a Sleep Sack (By Room Temperature)

If you've ever stood in the nursery at bedtime thinking, “Is my baby too warm… or not warm enough?” you’re not alone. Dressing baby for sleep can feel confusing fast, especially when you start seeing TOG ratings on sleep sacks.

This guide is here to make it simple. Below you’ll find an easy sleep sack TOG chart, plus practical outfit ideas for what to wear underneath based on room temperature.

A quick reminder, mama-to-mama: every baby runs a little different. These are helpful starting points, but your baby’s comfort cues always matter most. (More on that below.)

TOG is a warmth rating used on sleep sacks and baby sleeping bags to describe how much insulation the fabric provides. A lower TOG is cooler and lighter, while a higher TOG is warmer and more insulating.

Think of it like choosing a blanket weight, but in a wearable form that stays in place all night.

Use this chart as a general starting point for pairing your room temperature with a TOG rating, then adjust what baby wears underneath as needed. 

Room Temp (°F / °C) — Suggested TOG — What to wear underneath

• 75°F+ (24°C+) — 0.2–0.5 TOG — diaper only or a short‑sleeve bodysuit
  
  

• 72–75°F (22–24°C) — 0.5–1.0 TOG — short‑sleeve bodysuit
  
  

• 68–72°F (20–22°C) — 1.0 TOG — long‑sleeve bodysuit or lightweight pajamas
  
  

• 64–68°F (18–20°C) — 2.0–2.5 TOG — long‑sleeve bodysuit + warmer pajamas/footie
  
  

• Below 64°F (below 18°C) — 2.5–3.5 TOG — warm base layer + warmer pajamas (and consider warming the room)
  
  

Note: Brands may vary slightly in recommendations. Always follow the guidance that comes with your specific sleep sack.

Many families love 1.0 TOG because it works well in typical indoor temperatures, and you can adjust warmth by changing the layer underneath.

Here’s a simple cheat sheet for what baby can wear under a 1.0 TOG sack:

• Warm room (72–75°F): diaper + short‑sleeve bodysuit
  
  

• Comfortable room (68–72°F): long‑sleeve bodysuit or lightweight footie pajamas
  
  

• Cool room (65–68°F): footie pajamas, or a long‑sleeve bodysuit + lightweight pants
  
  

If your home gets very cold at night, you may prefer to warm the room rather than piling on heavy layers.

Instead of checking hands or feet (they can feel cool even when baby is perfectly comfortable), check baby’s chest or the back of the neck.

• Just right: chest feels warm and dry
  
  

• Too warm: sweaty neck/chest, flushed skin, restless sleep
  
  

• Too cold: chest feels cool and baby struggles to settle
  
  

This “check the chest/neck” approach is commonly recommended by baby sleepwear guides and pediatric sources. 

Warmth matters, but safety matters more.

• Keep the sleep space clear of loose blankets and soft items. Many pediatric safe sleep resources recommend avoiding loose bedding for babies and using wearable layers instead (1).
  
  

• Avoid weighted sleep products for infants (weighted sleep sacks, weighted swaddles, weighted blankets). U.S. safety agencies have issued warnings against them (2).

• Make sure your sleep sack fits properly around the neck and arm openings so it can’t ride up toward baby’s face.

If TOG has been making you feel like you need to “get it perfect,” here’s the truth: you don’t. The goal isn’t a flawless formula, it’s a calm routine you can repeat.

Start with the nursery temperature, choose the TOG that matches it, and put baby in one simple layer underneath; like a baby pajama or bodysuit. Then do the easiest comfort check in the world: feel baby’s chest or the back of the neck. Warm and dry? You’re good. Sweaty? Go lighter. Cool? Add one small layer.

And on nights when you’re second‑guessing everything (because motherhood can be like that), remember: you’re not failing. You’re paying attention, and that’s exactly what your baby needs.

References

1. CPSC, Safe Sleep – Cribs and Infant Products 

2. Cleveland Clinic, Are Sleep Sacks Safe for Babies?

3. Safe to Sleep (NICHD)