What is the maximum TOG on a baby sleeping bag under EN 16781?

What thermal cap does EN 16781 set?

UL's briefing for the British Retail Consortium groups overheating with the other main sleep-environment hazards the standard was written to limit. After the no-hood rule, it states that sleep bags are tested for thermal resistance and that EN 16781 requires a maximum of 0.40 m²·K/W (4.0 thermal overall grade).

SGS notes that tog values between 1 (very light) and 4 (padded) are commonly available, and that the child must not overheat overnight because overheating is a recognised contributing factor to SIDS. The standard also requires user information on choosing insulation for the home — it does not licence a bag thicker than the cap.

Have tests found sleeping bags thicker than 4.0 TOG?

Yes. Which?'s 2020 laboratory tests, run against extracts of BS EN 16781:2018, reported bags that exceeded the upper TOG level.

Official records show the standard cap is 4.0 TOG. A listing that boasts 'winter thick', '5 tog' or 'extra padded beyond 4' is advertising a value above that cap. Not found on the GOV.UK recall list does not mean the fill was tested to 0.40 m²·K/W.

Is the 4.0 TOG cap the same as a room-temperature chart?

No. The EN 16781 figure is a ceiling for the product. It does not tell you which tog to pick for tonight. NHS safer-sleep pages list commonly sold commercial ratings (for example 2.5, 1.0 and 0.5 tog) against room-temperature bands; that is dressing guidance, and it is a different question from whether a bag may be sold as 4.5 or 5.0 tog.

The Lullaby Trust does not publish its own tog-to-room table. It says every fabric stack traps heat differently, every baby is different, and you should follow the maker's tog guide, keep the room around 16–20°C as a guide, and check the chest or the back of the neck. It also says not to put two sleep bags on at once — trapped air between layers is not a simple 1.0 + 1.0 = 2.0.

If the room is cold, the standard's answer is not an illegal-thick bag. It is a bag at or under 4.0 TOG, extra clothing underneath if the chest feels cold, and no extra blankets on top of the bag — the Lullaby Trust line.

How do I read a 'winter thick' marketplace listing?

• Printed TOG above 4.0 — sits above the EN 16781 maximum UL quotes (0.40 m²·K/W / 4.0 TOG).
• No TOG at all — SGS lists thermal properties as something the standard requires; a blank listing has not shown you the cap.
• TOG that sounds precise but no BS EN 16781:2018 — Which? found printed ratings that did not match the lab.
• Two bags layered — Lullaby Trust says that is not how tog adds up and raises overheating risk.

Search the brand or listing on GOV.UK Product Safety Alerts, Reports and Recalls if you already own a thick bag. A notice may name overheating, a hood, or both. Not found ≠ the fill is at or under 4.0 TOG.

In shortEN 16781 caps a cot sleep bag at 0.40 m²·K/W, stated as 4.0 TOG. That is the thickest the standard allows, not a winter target. Which? has already measured listings above it. For the room you have tonight, use the maker's tog guide and Lullaby Trust checks — not a thicker bag than the cap.

Does the 4.0 TOG cap apply to weighted bags too?

Weighted fill is a separate design issue. UL says the draft revision of EN 16781 under discussion would not permit weighted sleep bags — bags with extra functional weighting to increase pressure on the body. That draft is not the current 2018 standard.

The Lullaby Trust already advises against weighted swaddles, blankets and sleeping bags for babies under one year, citing overheating, head covering, and pressure on a baby's chest. Do not read a 4.0 TOG cap as permission to add weight inside the same tog.

If you need a room-by-room clothing walk-through, that is a different page from this product cap. This article only covers the EN 16781 thermal maximum.