Quick answer
Use 2.5–4.5 tog for warm summer rooms, 7.5–10.5 tog for spring/autumn or heated bedrooms, and 12–13.5 tog for cold winter rooms. Hot sleepers generally need less; young children need age-appropriate guidance rather than the adult chart.
Tog rating by typical use
| Tog | Typical use | Room context | Best for |
|---|---|---|---|
| 2.5–4.5 | Summer | Warm or hot room | Hot sleepers and warm nights |
| 7.5 | Late spring / early autumn | Mild room | Flexible transitional warmth |
| 10.5 | All-season / mild winter | Moderate or heated room | Most average sleepers |
| 12–13.5 | Winter | Cool bedroom | Cold sleepers and winter nights |
| 15 | Very cold conditions | Unheated, very cold room | Only sleepers who genuinely need high insulation |
What tog actually measures
Tog is a measure of thermal resistance: a higher number slows heat loss more. It does not tell you how heavy, breathable, durable or luxurious a duvet is.
A lofty down duvet can achieve warmth with less physical weight than many synthetic products. Compare fill construction alongside tog, especially if you dislike heavy bedding.
- Higher tog means more insulation
- Tog is not the same as fill weight
- Two fills can share a tog but feel different
- Breathability still matters to hot sleepers
Choose for the room, not the calendar
Bedroom temperature is more useful than the month. A centrally heated flat may need less insulation in January than a cool stone house needs in October.
If your room changes significantly, an all-seasons pair—often a light and medium duvet that fasten together—gives more flexibility than one very warm duvet.
- Warm room: 2.5–7.5 tog
- Moderate room: 7.5–10.5 tog
- Cool room: 10.5–13.5 tog
- Variable room: consider an all-seasons pair
Adjust for the sleeper
Hot sleepers should start below the seasonal default and favour breathable shells and moisture-managing fills. Cold sleepers can move up one warmth band before adding multiple loose blankets.
Babies and young children regulate temperature differently. Use age-specific safe-sleep advice and the product manufacturer's age guidance rather than applying an adult tog chart.
- Hot sleeper: reduce insulation
- Cold sleeper: increase one band
- Couples: consider two separate duvets
- Children: use age-specific safe-sleep guidance
Frequently asked questions
Is 10.5 tog for summer or winter?
A 10.5 tog duvet is usually an all-season or cooler-bedroom choice rather than a hot-summer duvet. It suits many UK bedrooms in spring and autumn and some well-heated winter rooms.
Source: John Lewis, Dunelm, Marks & Spencer
How many tog should my duvet be?
Match tog to room temperature and personal warmth: roughly 2.5–4.5 for warm summer rooms, 7.5–10.5 for transitional seasons or moderate rooms, and 12–13.5 for cold winter bedrooms.
Source: John Lewis, Dunelm, Marks & Spencer
Is 13.5 tog warm enough for winter?
For many adults in an unheated or cool UK bedroom, 13.5 tog is a warm winter option. Hot sleepers or centrally heated rooms may be more comfortable around 10.5 tog.
Source: John Lewis, Dunelm, Marks & Spencer
Is 7.5 tog too warm for summer?
It may be too warm during hot spells, especially in an upstairs bedroom. It can work in a cool summer room or for a cold sleeper, while 2.5–4.5 tog is the usual warm-weather range.
Source: John Lewis, Dunelm, Marks & Spencer
Sources and methodology
We cross-checked practical guidance against manufacturer care instructions and established editorial or standards sources. Always follow the sewn-in care label on your own product.