Answer three quick questions and get the right tog for your duvet — for the season, your bedroom, and how warm you sleep.
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A versatile all-rounder that suits most people for much of the year.
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A quick reference for matching tog to the time of year.
| Tog rating | Best for | Who it suits |
|---|---|---|
| 1 – 4.5 tog | Summer | Hot sleepers, heated bedrooms, warm nights |
| 7.5 tog | Late spring / early autumn | Mild nights, transitional weather |
| 9 – 10.5 tog | Spring & autumn | Most people, most of the year |
| 12 – 13.5 tog | Winter | Cold nights, cooler bedrooms |
| 15 tog | Deep winter | Very cold rooms, people who always feel the chill |
A tog rating measures the thermal resistance — the insulation — of a duvet or blanket. It's a simple warmth scale used mainly in the UK: the higher the tog, the warmer the duvet, because it traps more warm air around you.
Crucially, tog is about warmth, not thickness. A natural down duvet can be light and thin yet very warm, while a bulkier synthetic one might have a lower tog. That's why it pays to check the rating rather than judge by feel. Pick the tog that matches the season and how warm you sleep, and you'll be comfortable without a duvet that's too heavy or too cold.
It depends on the season and how warm you sleep. As a rule of thumb: 1–4.5 tog for summer, 9–10.5 tog for spring and autumn, and 13.5 tog for winter. Use the calculator above for a recommendation tailored to your bedroom and sleep style.
13.5 tog is a winter weight built to trap warmth on cold nights. It can feel too warm in summer, in a heated bedroom, or if you're naturally a hot sleeper — in those cases drop to 9–10.5 tog or lower.
A 9–10.5 tog duvet suits most people for much of the year. If you want one duvet for every season, look for an all-seasons set: a 4.5 tog and a 9 tog duvet that press-stud together to make around 13.5 tog for winter, and split apart for summer.
If you tend to overheat, drop a level from the seasonal norm — a 4.5–7.5 tog duvet often works even in spring and autumn, and many hot sleepers stay comfortable in a lightweight duvet year-round in a heated home.
Babies need much lower togs, and safety guidance is different from adults. The Lullaby Trust advises against duvets and pillows for babies under 12 months. For older babies and toddlers, use a low tog (around 2.5–4 tog) and always follow current infant-safe-sleep guidance. This calculator is for adult bedding.
No — tog measures insulation, not thickness. A down duvet can be warm yet thin and light, while a chunkier synthetic duvet may have a lower tog. Always go by the tog rating.