How to Choose the Right TOG Rating for Your Baby's Sleep Environment

Quick answer

To choose the right TOG rating, match the sleep bag's TOG to the room temperature: 0.2 TOG for 24–27°C, 1.0 TOG for 21–23°C, 2.5 TOG for 17–20°C, and 3.5 TOG for 13–16°C. Always check your baby's chest to ensure they're warm but not sweaty.

Understanding TOG ratings is key to keeping your baby comfortable and safe during sleep. TOG (Thermal Overall Grade) measures the warmth of a sleep bag, and choosing the right one depends on the temperature of the room where your baby sleeps.

This guide breaks down how to select the appropriate TOG, how to layer clothing underneath, and how to adjust as seasons change. We'll also highlight product bundles that offer versatility for changing temperatures.

What is a TOG rating and why does it matter?

TOG rating indicates the thermal insulation of a fabric. The higher the TOG, the warmer the sleep bag. Using the correct TOG helps prevent overheating, which is a risk factor for SIDS, and ensures your baby doesn't get too cold. A sleep bag with a TOG too high can cause sweating and discomfort, while one too low may lead to waking from cold.

Room temperature is the primary factor in choosing TOG. Always measure the temperature in the room where your baby sleeps, not the whole house. Use a reliable room thermometer to get an accurate reading.

• Check room temperature at the start of the night and during middle-of-the-night wakes.
• Feel your baby's chest or back to gauge temperature—not hands or feet, which are often cooler.

TOG guide by room temperature

A general TOG guide for baby sleep bags is as follows: 0.2 TOG for warm rooms (24–27°C), 1.0 TOG for rooms 21–23°C, 2.5 TOG for 17–20°C, and 3.5 TOG for cooler rooms (13–16°C). These ranges are starting points; adjust based on your baby's individual needs and the clothing layers underneath.

For example, if your room is 22°C, a 1.0 TOG sleep bag is ideal. If you use a cotton sleepsuit underneath, that's sufficient. In cooler months, you might combine a 2.5 TOG bag with a long-sleeved layer for extra warmth.

• Always remove hats and extra blankets when using a sleep bag to reduce overheating risk.
• Keep the nursery between 16–20°C for optimal sleep, if possible.

Layering: how to adjust under a sleep bag

Layering allows you to adapt the sleep bag to the exact temperature. If the room is between recommended ranges, you can add or remove a layer. For instance, in a 20°C room, a 2.5 TOG bag with a short-sleeved onesie might be enough, but if it's cooler, add a long-sleeved layer.

Always choose layers made of breathable fabrics like cotton or bamboo. Avoid bulky clothing that can cause your baby to overheat. The sleep bag itself should fit snugly around the chest and shoulders, with no room for the baby to slip down inside.

• Use the 'chest test': your baby's chest should feel warm, not hot or sweaty.
• If your baby's hands feel cool but chest is warm, they are comfortable.

Seasonal strategies and product bundles

Many parents prefer to have two or three TOG options to handle seasonal changes. A 1.0 TOG bag works for spring and autumn, while a 2.5 TOG is ideal for winter. Some brands offer bundles that include both, saving money and ensuring you have the right TOG on hand.

For example, ergoPouch's Premium Sleeping Bag 1.0 & 2.5 TOG Bundle includes both warmth levels, so you're ready for changing temperatures throughout the year. Similarly, the Spring Sleeping Bag Bundle offers a 1.0 and 2.5 TOG combination, perfect for transition seasons. For warmer months, the Summer Sleep Suit Bag Pack includes a 0.2 TOG and 1.0 TOG option, covering summer and mild nights.

• Consider your local climate and how quickly temperatures change.
• Bundles can be cost-effective, often saving 20% off the individual RRP.

Special considerations: higher TOG and alternatives

For very cold rooms or babies who sleep cool, a 3.5 TOG sleep bag provides extra warmth. For example, the Sleep Onesie 3.5 TOG is a TOG-rated alternative to a traditional sleep bag, designed to be worn on its own or with a layer underneath. It's a good option for toddlers who prefer more freedom of movement.

Remember, even with a high TOG, always check your baby's temperature. Overheating is a risk, so never add extra blankets on top of a sleep bag. If your baby is sweating, remove a layer or choose a lower TOG.

• 3.5 TOG bags are typically for rooms 13–16°C; use with caution in warmer rooms.
• If your baby outgrows sleep bags, consider a sleep onesie for older toddlers.

Decision rules for choosing TOG

• Measure room temperature: Use a reliable thermometer to check the room temperature where your baby sleeps. Do this at the start of the night and again if you wake during the night. Room temperature is the foundation of TOG selection.
• Match TOG to temperature range: Refer to the TOG guide: 0.2 TOG for 24–27°C, 1.0 for 21–23°C, 2.5 for 17–20°C, 3.5 for 13–16°C. Choose the closest TOG to your room's temperature. Select the TOG that aligns with your measured temperature.
• Adjust with layers: If your room temperature falls between two TOG ranges, use a lighter sleep bag and add a layer underneath, or use a warmer bag with fewer layers. Always use breathable fabrics. Layering gives you flexibility without buying multiple bags.
• Check your baby's temperature: Feel your baby's chest or back. If it's warm and dry, the TOG is appropriate. If sweaty, remove a layer or choose a lower TOG. If cool, add a layer or increase TOG. Your baby's comfort is the ultimate indicator.
• Consider seasonal bundles: If you expect significant temperature changes, consider a bundle with multiple TOGs to save money and always have the right option. Bundles like the Premium Sleeping Bag 1.0 & 2.5 TOG Bundle offer year-round versatility.

Products to help you get the right TOG

• Premium Sleeping Bag 1.0 & 2.5 TOG Bundle: Save 20% Off RRP with our 1.0 TOG & 2.5 TOG Premium Sleeping Bag Bundle. With two warmth levels included, you'll be ready for changing temperatures and comfortable sleep throughout the year. This bundle covers most of the year, so you don't have to buy separate bags for different seasons. It's a cost-effective way to ensure you have the right TOG for spring, autumn, and winter.
• Spring Sleeping Bag Bundle: Be ready for changing temperatures with our Spring Sleeping Bag Bundle, featuring two versatile sleeping bags designed to keep your little one comfortable through the season. 1 x Sleeping Bag 1.0 TOG and 1 x Sleeping Bag 2.5 TOG. If you live in a region with unpredictable spring weather, this bundle gives you both a lighter and a warmer option, so you can adapt to sudden temperature drops or warmer days.
• Summer Sleep Suit Bag Pack: Save 20% OFF RRP with the Summer Sleep Suit Bag Pack. 1 x Jersey Sleep Suit Bag 0.2 TOG and 1 x Sleep Suit Bag 1.0 TOG. For hot summer nights, a 0.2 TOG bag is essential. This pack also includes a 1.0 TOG for cooler evenings or air-conditioned rooms, making it a versatile choice for summer.
• Sleep Onesie 3.5 TOG: The Sleep Onesie is a TOG-rated sleeping bag alternative, designed to be worn on its own during sleep or with a Layer/PJs underneath for warmth and comfort. If your baby is older and prefers more leg movement, a 3.5 TOG sleep onesie provides deep warmth for cold winter nights without the restriction of a traditional sleep bag.

Fit and suitability

Best for

• Parents who want a simple, safe sleep solution without loose blankets
• Babies who sleep arms out and are 8 months or older (wider-fit sleeping bags)

Not for

• Newborns who need swaddling (consider a swaddle or cocoon instead)
• Parents who prefer using blankets and are comfortable with safe bedding practices

Choosing the right TOG rating doesn't have to be complicated. Measure your baby's room temperature, match it to a TOG range, and adjust with layers as needed. Trust your baby's cues—if they're comfortable, you've got it right. With the right sleep bag, both you and your baby can enjoy restful nights.