Choosing a Baby Sleeping Bag: Safety Standard, Fit and Tog Explained

A baby sleeping bag is one of the simplest nursery purchases and one of the most useful: a wearable layer that replaces loose bedding. With dozens of designs, sizes and tog ratings on sale, a few clear rules make choosing easier. This guide sets out what the Lullaby Trust, the UK’s safer sleep charity, says to look for when buying one.

Why a sleeping bag rather than loose bedding

The Lullaby Trust describes baby sleeping bags as a good option for safer sleep because they stop a baby from wriggling down under covers and getting their head covered (The Lullaby Trust, “How to dress your baby for sleep”). Its product guide lists a sleeping bag, or sheets and a lightweight blanket, among the few items it recommends, and says there is no need to buy lots of products or spend money on expensive items (The Lullaby Trust, “Baby sleeping products”). A well-chosen sleeping bag therefore does not need to be a premium purchase.

Step one: look for the British Standard

The Lullaby Trust strongly recommends that any sleep product meets the relevant British Standards, especially when bought online. It explains that a British Standard shows the product has passed certain safety tests, such as making sure it will not fall apart or easily catch fire. The standard for baby sleeping bags is BS EN 16781:2018. Its product page adds that if a product meets British Safety Standards, it should say so on the product itself, its packaging, the instructions or the website.

The Trust’s product guide also makes a useful point about marketing. It says there are no rules or regulations that look specifically at whether a product makes safer sleep more or less likely, and that most safety standard checks cover other issues such as construction, chemicals and fire safety (The Lullaby Trust, “A guide to buying safer sleep essentials”). In practice, that means the standard code is a better guide than a bold claim on the front of the packaging.

Step two: get the size right

Fit matters as much as the label. The Lullaby Trust says a sleeping bag should be well fitted around the neck and shoulders, so that the baby cannot wriggle down inside. Its product guide adds that the bag should fit well around the shoulders so the baby’s head does not slip down into it, and that no extra bedding is needed.

Sizes are usually chosen by weight. According to the Trust, most baby sleeping bags are fitted by weight, not age, so the manufacturer’s guidelines should always be checked. The product guide notes that different sizes are available depending on the baby’s age, and that different togs can be chosen for different seasons.

Step three: understand the tog rating

Tog is the measure of warmth printed on the bag. The Lullaby Trust says to follow the manufacturer’s tog guide to choose the right tog for the room temperature. Two further points from its guidance help avoid mistakes at the shop or when building a small collection:

• Do not add blankets on top of a sleeping bag. If more warmth is wanted, the Trust suggests an extra layer of clothing or a higher tog bag.
• Do not double up. Dressing a baby in two 1.0 tog sleeping bags does not make a 2.0 tog bag, the Trust says, because air becomes trapped between layers and increases the warmth.

The same guidance says the Trust is unable to provide a chart matching room temperature to clothing layers and tog, because every product is made from different materials with different insulation, and every baby is different. The manufacturer’s own guide is therefore the reference point for a specific bag.

What to leave on the shelf

The Lullaby Trust says weighted swaddles, blankets and sleeping bags are not recommended for babies under one year. Anyone considering a novelty or “calming” sleepwear product should check it against that statement. The product page also lists items the charity advises avoiding for sleep more generally, including soft pods or nests, pillows, duvets, cot bumpers and sleep positioners.

Second-hand and recalls

Sleeping bags are easy to find second-hand, but the Lullaby Trust says to check for product recalls before using second-hand baby items. Its product page lists recent safety alerts, some involving sleeping bags, and its product guide suggests searching “product recalls” on GOV.UK to see whether problems have been identified with a potential purchase. Our guide to second-hand and sustainable baby gear covers wider checks. A recall search takes only a few minutes and is worth doing before buying used.

A quick shopping checklist

• Look for BS EN 16781:2018 on the product, packaging, instructions or website.
• Choose the size by the baby’s weight, following the manufacturer’s chart.
• Check the neck and armholes fit closely enough that the baby cannot slip down inside.
• Read the manufacturer’s tog guide and pick a tog for the season.
• Skip weighted designs.
• Buy a spare of the same tog, or two togs for different seasons, rather than layering bags.
• Search for recalls, particularly on a second-hand purchase.

The bottom line

The Lullaby Trust recommends a baby sleeping bag as an alternative to loose bedding. When buying one, look for BS EN 16781:2018, choose a size by the baby’s weight so it fits snugly around the neck and shoulders, and follow the manufacturer’s tog guide. Do not add blankets over the bag, do not double up two bags, and avoid weighted versions for babies under one. A quick recall check makes second-hand purchases safer.

Sources

• The Lullaby Trust, “How to dress your baby for sleep”
• The Lullaby Trust, “Baby sleeping products”
• The Lullaby Trust, “A guide to buying safer sleep essentials”