What should my baby sleep in?
Finding the right sleepwear for your baby can feel overwhelming, especially with so many options available. Whether you’re considering a swaddle, a sleeping bag, or a sleepsuit, we’re here to help you choose the right one for your baby’s stage. This guide explains the benefits of each option, what TOG ratings mean, and how to choose the right sleepwear based on your baby’s age, stage, and room temperature.
Swaddle, sleeping bag or sleepsuit?
The three serve different stages, and most families use more than one as their baby grows. Here’s the quick version.
Swaddle
Best for newborns not yet rolling
Designed to recreate the snug, secure feeling of the womb, a swaddle helps calm your baby’s natural startle reflex and encourages more settled sleep from day one.
Sleeping bag
Best from birth through toddlerhood
A wearable blanket designed to keep your little one cosy, comfortable and covered throughout daytime naps and nighttime sleeps. By replacing loose blankets, it helps maintain a consistent sleep environment and supports more settled sleep as your baby grows.
Sleepsuit
Best for when your baby starts walking
Perfect for little ones transitioning from sleep to play, the sleepsuit offers all the comfort and reassurance of a sleeping bag with added freedom to move. Featuring built-in grip socks for extra stability, it supports growing toddlers as they walk, explore and play, while keeping them cosy without the need for loose blankets.
1. Swaddle
A swaddle wraps your baby snugly in lightweight fabric with their arms gently tucked in. It mimics the closeness of the womb and helps settle the Moro (startle) reflex - the involuntary jump that wakes newborns. For many families it’s the difference between a baby who startles awake and one who settles.
- Who it’s for: newborns, from birth.
- Always on their back: never put a swaddled baby down on their side or front.
- Snug, not tight: legs need to bend up and out at the hips for healthy hip development.
- Lightweight only: use thin fabric and never add a blanket on top.
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View all →2. Sleeping bag
A baby sleeping bag is a wearable blanket with armholes and no legs. It’s the product most families use for the longest, because it keeps your baby at a steady temperature without loose blankets that can ride up over their face. Our SnüzPouch sleeping bags add a handy nappy-change zip for quick, minimal disturbance night changes.
- From birth — provided your baby meets the minimum weight on the label.
- Well-fitted around the neck and shoulders so baby can’t slip down inside.
- No loose bedding to kick off or pull over the face.
- A clear bedtime cue — bag on means sleep time, wherever you are.
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View all →3. Sleepsuit
A sleepsuit is a wearable, togged suit with legs and arms. Where a sleeping bag is open at the bottom, a sleepsuit allows a mobile little one the freedom to move - ideal once your little one is too active for a sleeping bag.
- Who it’s for: babies who are standing, cruising or walking.
- Togged like a bag: match the TOG to the room temperature and layer underneath.
- Travel-friendly: keeps an active baby covered on the go.
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View all →4. Understanding TOG ratings
TOG (Thermal Overall Grade) measures how much warmth a fabric traps — the higher the number, the warmer the product. Baby sleep products are deliberately capped at low TOGs because babies overheat far more easily than adults, and overheating raises the risk of SIDS.
The number that matters most is the room temperature. The Lullaby Trust, the UK’s leading safer-sleep charity, recommends keeping the room your baby sleeps in at 16–20°C. A simple room thermometer takes out the guesswork.
| Room temperature | TOG | What to wear underneath |
|---|---|---|
| Above 24°C (heatwave) | 0.5 TOG | Just a nappy, or a short-sleeve bodysuit |
| 20–24°C | 1.0 TOG | Short-sleeve bodysuit, or a light babygro |
| 16–20°C (most of the year) | 2.5 TOG | Long-sleeve bodysuit + a footed babygro |
| Below 16°C (chilly room) | 2.5 TOG + layer | Add a clothing layer under a 2.5 TOG rather than a blanket on top |
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5. Choosing the right size
Baby sleeping bags and swaddles are sized by weight (and sometimes height), not age - that’s what keeps them well-fitted around the neck and shoulders so your baby can’t wriggle down inside. A bag that’s too big is a safety risk; one that’s too small is uncomfortable.
- Always check the weight range on the label before buying.
- Our SnüzPouch sizes run 0–6m, 6–18m and 18–36m - check the size guide for the matching weights.
- Buy for your baby’s current weight, not the size you hope they’ll grow into.
6. Safer sleep essentials
Whatever your baby sleeps in, these basics apply every time:
- Always put your baby down on their back, on a firm, flat, waterproof mattress.
- Keep the cot clear — no pillows, duvets, bumpers or soft toys for babies under one.
- Keep the room at 16–20°C and dress for the temperature.
- Never add blankets on top of a sleeping bag or swaddle — change the layer of clothing or the TOG instead.
- Follow the manufacturer’s guidance on weight, fit and TOG for the product you buy.
Frequently asked questions
What TOG sleeping bag do I need for winter?
What TOG do I need for summer?
Can a newborn use a sleeping bag?
When should I stop swaddling?
Do I need a blanket as well as a sleeping bag?
How do I know which size to buy?
Still not sure? Let us help.
Answer three quick questions and we’ll recommend the right product, TOG and size for your little one.
This guide is general information to help you choose a product and is not medical advice. Every baby is different - always check your baby isn’t too hot, follow the guidance on your product’s label, and see The Lullaby Trust and the NHS for full safer-sleep advice.