Tog Rating Chart: The Right Duvet for Every Season

calendar Jun 6, 2026 / · 5 min read · togs bedding duvet tog-rating uk  ·
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What a tog rating actually tells you

The first frost of the year is usually when the question arrives. The heating clicks off overnight, the bedroom drops a few degrees, and a duvet that felt perfectly comfortable in October suddenly leaves a cold gap along one shoulder. The instinct is to reach for "something warmer" — but warmth in a duvet is not a vague quality. It is measured, standardised, and printed on the packaging as a single number: the tog rating.

A tog is a unit of thermal resistance. The higher the number, the more effectively the duvet slows the escape of body heat, and the warmer the bed feels. According to the British Standards definition of the unit, one tog corresponds to a specific amount of insulation, so the scale is consistent across brands — a 13.5 tog duvet from one retailer should keep you about as warm as a 13.5 tog duvet from another, regardless of the filling. That is the whole point of the rating: it lets you compare warmth without unpicking the duvet.

Crucially, a tog rating measures insulation, not weight. A high-fill-power down duvet can hit 13.5 tog while staying light and lofty, whereas a microfibre duvet may need more material to reach the same figure. UK retailers such as Dunelm and consumer testers at Which? organise their entire bedding ranges around this number, which is why understanding the chart is the fastest route to the right duvet.

The tog rating chart by season

Most UK households can map their bedding to the calendar with a single chart. The figures below are the industry-standard bands used across British retailers:

Tog ratingSeasonTypical use
1.0–4.5SummerWarm nights, heated bedrooms, hot sleepers
7.0–9.0Spring / autumnMild shoulder seasons, transitional weather
10.5All-seasonYear-round comfort in a temperate home
12.0–13.5WinterCold bedrooms, unheated rooms, cold sleepers
15.0Ultra-warmVery cold rooms, draughty period homes, the coldest sleepers

The bands overlap deliberately. Your ideal tog depends as much on your bedroom temperature and personal metabolism as on the month — a naturally warm sleeper in a well-insulated flat may stay in a 7.5 tog duvet through December, while someone in a draughty Victorian terrace reaches for 13.5 tog by November.

Summer: 4.5 tog and below

A 4.5 tog summer duvet is built to be barely there. It provides enough cover to feel settled without trapping heat, which matters during a British heatwave when even a thin duvet can feel oppressive. Hot sleepers and anyone with a consistently warm bedroom often keep a 4.5 tog on the bed well beyond summer. Natural fillings such as cotton or a low-fill down breathe better than dense synthetics at this weight, helping wick moisture on muggy nights.

Spring and autumn: 7.5 to 9 tog

The shoulder seasons are where a single duvet struggles most, because daytime mildness can swing to a chilly 3am. A 7.5 or 9 tog duvet is the classic compromise — substantial enough for a cool spring evening, light enough that you will not overheat when an unseasonably warm night arrives. Households that prefer not to swap duvets twice a year often settle here or step up to all-season.

All-season: 10.5 tog and the duvet-pairing trick

A 10.5 tog all-season duvet is the most popular single choice in the UK for good reason: it sits in the comfortable middle of the chart and suits a centrally heated home for most of the year. But the smarter option for households that feel the cold is an all-seasons pair: a 4.5 tog and a separate 9 tog duvet that clip or button together. Used alone they cover summer and autumn; combined, they reach roughly 13.5 tog for deep winter. One purchase covers the entire chart.

Winter: 13.5 tog and ultra-warm 15 tog

When the heating goes off overnight and the bedroom genuinely cools, a winter-weight duvet earns its place. A 13.5 tog winter duvet is the standard UK winter choice and suits most cold bedrooms. The rare 15 tog rating is reserved for the coldest situations — unheated rooms, draughty period properties, or people who simply never feel warm enough. Above 13.5 tog, filling quality matters more than the number: a poorly made ultra-warm duvet can feel heavy and clammy rather than cosy.

How to choose your tog rating

Start with your bedroom, not the season. Measure how cold the room actually gets overnight — a thermostat reading at 6am tells you more than the month on the calendar. Then factor in whether you sleep hot or cold, and whether you would rather own one all-season duvet or a summer/winter pair. If you are between two ratings, most UK sleepers are better served sizing down slightly, since an over-warm bed disrupts sleep more than a marginally cool one. For the precise meaning of the word "tog" — and why the same word also describes swimwear across the Commonwealth — see what does togs mean.

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