Tog measures how well a duvet traps warm air — the higher the tog, the warmer the duvet. The UK scale runs from about 1 tog (coolest) to 15 tog (warmest standard weight). Choose 4.5 for summer, 7.5–10.5 for spring and autumn, and 13.5–15 for winter.
Tog stands for Thermal Overall Grade — a lab measure of a duvet's thermal insulance, in other words how well it holds warm air against you. It is not a measure of thickness or weight. A lightweight down duvet and a bulkier hollowfibre duvet can share the same tog rating yet feel very different in loft and drape, because the fill reaches that warmth in different ways.
The higher the tog, the more warmth the duvet retains. What matters for comfort is matching that warmth to your room, not chasing the biggest number. One thing worth clearing up: "tog" applies to duvets only — it is not used to rate pillows or mattress toppers.
| Tog | Best for |
|---|---|
| 1–3.5 tog | Children's, travel and very hot rooms — the lightest option |
| 4.5 tog | Standard summer weight — 4.5 Tog Duvet |
| 7.5 tog | Spring and early autumn — 7.5 Tog Duvet |
| 10.5 tog | All-season and heated homes — 10.5 Tog Duvet |
| 12–13.5 tog | Winter warmth — 13.5 Tog Duvet |
| 15 tog | Coldest rooms, warmest standard weight — 15 Tog Duvet |
A handful of brands market 16.5–18 tog duvets; above that, claimed ratings aren't meaningful and the extra weight harms sleep comfort. To go warmer than 15, layer instead — a 4.5 over a 10.5 traps more air than one very heavy duvet.
| Season | Recommended tog | Shop |
|---|---|---|
| Summer | 4.5 tog | 4.5 Tog Duvet |
| Spring / early autumn | 7.5 tog | 7.5 Tog Duvet |
| All year / heated homes | 10.5 tog | 10.5 Tog Duvet |
| Winter | 13.5 tog | 13.5 Tog Duvet |
| Coldest rooms / deep winter | 15 tog | 15 Tog Duvet |
The season is only a starting point — your room matters more. If your heating stays on overnight, drop a level: a heated bedroom in winter often suits 10.5 rather than 13.5. If your room is unheated or single-glazed, rise a level to hold the warmth in.
A memory foam mattress traps and reflects your body heat, so many people find they can drop a level and stay comfortable. And where two people share a bed, the warmer sleeper effectively wins — compromise on the cooler tog, or use the "Scandinavian method" and split the bed with two single duvets, each person choosing their own tog.
Safety comes first with young children. Babies under 12 months should not use a duvet at all — use firmly tucked, breathable blankets and follow current safer-sleep guidance instead. From 1 to 3 years, keep to a maximum of around 4 tog. Older children can move to 4.5 up to 10.5 tog, chosen by room temperature rather than age.
Always keep bedding well fitted and the room comfortably cool, and check the latest safer-sleep advice from a trusted source such as The Lullaby Trust if you are unsure.
Thermal Overall Grade — the lab standard for measuring how much warmth a duvet retains.
Commonly 4.5, 7.5, 10.5, 13.5 and 15 — the range we stock; anything above roughly 15–18 isn't a meaningful standard.
There's no single best — 10.5 is the most versatile for heated UK homes; match tog to your room, not the calendar.
10.5 is the typical year-round choice; UK households often own a 4.5 and a 13.5 and switch seasonally.
Not necessarily — tog measures warmth, not weight; modern fills reach high togs while staying light.
Most UK hotels run 10.5 all year with climate control — part of why hotel beds feel consistent.
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