A baby sleeping bag is chosen according to two criteria: the size, which must let the head pass through without ever allowing the body to slip inside, and the TOG rating, which indicates the model's insulating capacity. The correct choice always depends on the actual room temperature, measured rather than estimated. Everything else—material, sleeves, length—relates to comfort and the season.
What is a baby sleeping bag for, and why has it replaced the blanket?
A baby sleeping bag is a wearable sleeping bag. It keeps the child warm without covering the face, and it does not move around when the baby moves. This is precisely what distinguishes it from a blanket or sheet.
French recommendations for infant sleep are explicit on this point. The bed must remain empty: no pillow, no duvet, no crib bumper, no stuffed toy. We explain these rules in detail in our article on safe infant sleep.
A baby sleeping bag solves this problem simply. It provides the necessary warmth while keeping the sleeping surface clear. This is why it has become standard both in maternity wards and at home.
What size baby sleeping bag for each age?
Size is measured in centimeters of the sleeping bag's total height, not by age. Age guidelines shown by manufacturers are indicative and vary widely from one brand to another. Rely on your child's height.
Common sizes
- 50 to 60 cm: from birth to approximately 4 months, for a child measuring 50 to 65 cm.
- 70 cm: approximately 4 to 12 months, for a child measuring 65 to 80 cm.
- 90 cm: approximately 12 to 24 months, for a child measuring 80 to 95 cm.
- 110 cm and above: over 2 years old, as long as the child accepts the sleeping-bag format.
There is a simple rule to decide. The sleeping bag should extend ten to fifteen centimeters beyond the child's feet, without excess. If it is too short, it restricts the legs and the child quickly complains. If it is too long, it leaves unnecessary bulk at the bottom of the bed.
The neckline and armholes: the real safety criterion
Neck and armhole circumference matter more than length. The opening should let the head pass through without forcing, then remain snug once the garment is on. If you can slide your entire hand between the neck and the fabric, the model is too wide.
The risk with an opening that is too large is that the child may slip down inside the bag during the night. European standard EN 16781 specifically regulates these dimensions for children’s sleeping bags. A compliant model will mention this on its label.
This habit of checking the label applies to all bedroom equipment. Our guide on how to read a product specification sheet explains how to identify the information that really matters.
TOG: how to read the rating and match it to the bedroom temperature
TOG measures the thermal resistance of a textile. The higher the rating, the more insulating the model. It is not a safety standard but a unit of thermal comfort, also used for adult bedding.
TOG and room temperature correspondence
- 0.5 TOG: room between 24 and 27°C, hot periods, summer nights.
- 1 TOG: room between 21 and 24°C, mild transitional seasons.
- 2 to 2.5 TOG: room between 18 and 21°C, the most common range year-round.
- 3 TOG and above: room below 18°C, winter in an unheated room.
The recommended temperature for a child’s bedroom is between 18 and 20°C. A room thermometer placed at bed height costs little and eliminates guesswork. It is the only reliable way to choose the right TOG rating.
What to wear underneath
A sleep sack should never be worn alone over an overly thick sleepsuit. The usual rule is to count one fewer layer than an adult would wear in the same room. A short-sleeved bodysuit is enough under a 0.5 TOG model in summer.
In winter, a cotton or velour sleepsuit under a 2.5 TOG model covers most situations. Check the temperature at the nape of the neck or between the shoulder blades, never on the hands or feet, which are naturally cooler. A damp nape indicates overheating.
This layering approach also applies when going out. We have covered it in detail in our article on how to dress a baby in cold weather.
Sleeping bag or turbulette: what’s the difference?
None, in everyday use in France. “Turbulette” is a registered trademark that has become a generic name, like “Frigidaire.” Both words refer to the same baby sleeping bag. However, some manufacturers reserve the term turbulette for lightweight sleeveless styles, but this distinction is not official.
Which materials should you choose?
Cotton remains the standard choice for the lining, the part that touches the skin. It is breathable, washable at high temperatures, and ages well. Organic cotton and OEKO-TEX Standard 100-certified fabrics limit chemical residues.
The filling determines the TOG rating. Polyester wadding is the most common and the easiest to wash. Down provides more insulation at the same weight, but it is difficult to wash and costs significantly more. Cotton muslin, in several layers, offers a breathable alternative for temperate rooms.
Beware of unnecessary embellishments. Embroidery, appliqués, and decorative ribbons add weak points and sometimes small detachable parts. The same requirement for material simplicity applies to all baby products, as we explain in our guide to foam mat materials and safety.
Sleeves, sleeveless, or with legs: which style for which use
The sleeveless style is the standard format. It leaves the arms free, prevents overheating, and is suitable for a properly heated room. It is the default choice for nighttime.
Styles with removable sleeves provide greater flexibility during the transitional seasons. Remove the sleeves when the room warms up, without changing the sleeping bag. Make sure the sleeve fasteners do not contain any small parts that could come loose.
The sleeping bag with separate legs is intended for children who walk. It allows them to move around without the risk of falling, which becomes useful when the crib opens or the child gets up on their own. It rarely becomes appropriate before eighteen months.
Finally, the thick styles known as “outdoor” sleeping bags are used in strollers or for naps outdoors. This Nordic practice is common in Scandinavia, and we have devoted an article to it on outdoor naps.
How many to plan for, and how to care for them
Two models per season are enough in the vast majority of cases. One is in use while the other dries or waits in case of a nighttime accident. Buying more means storing textiles that will be too small before they have been used.
Wash at 40 °C for routine care, and at 60 °C in case of spit-up or leakage. Tumble-drying at a low temperature helps preserve the filling. Washing before first use removes manufacturing finishes.
A well-chosen sleeping bag can easily be passed down between children or bought secondhand. In that case, check the condition of the zippers, snaps, and filling, which tends to become compressed. Our guidelines on caring for childcare products apply directly.
The most common mistakes
- Choosing a size ahead. A sleeping bag that is too large negates the safety benefit. It is better to choose the right size and replace it more frequently.
- Ignoring the room temperature. TOG only has meaning when combined with an actual measurement.
- Adding a blanket on top. The sleeping bag replaces the blanket; it does not supplement it.
- Keeping a damaged model. A zipper that catches or compressed filling are reasons to replace it.
- Confusing warmth with comfort. An overdressed child sleeps poorly and sweats.
Sleeping bag at night, on the floor during the day
The sleeping bag takes care of nighttime. During the day, children need the opposite: a clear, firm space without restrictions, where they can roll, crawl, and sit up freely. These two periods complement each other.
Choosing a mattress follows the same principles of firmness and proper dimensions as choosing a sleeping bag. Our guide on how to choose a baby mattress safely explains these criteria in detail.
A question about sizes, materials, or our certifications? Our frequently asked questions page brings together the most commonly requested answers.
