Tog Rating Chart: The Right Duvet for Every Season

What tog should your duvet be?

Choosing between a 10.5 and a 13.5 tog duvet comes down to how cold your bedroom gets at night, more than the month on the calendar. The tog number on a UK duvet measures how well it keeps heat in: the higher the number, the warmer the duvet. This page puts the main UK retailers' seasonal guides side by side, so you can see where they agree, where they differ, and what the number does not tell you.

A tog is a unit of thermal resistance. According to Wikipedia's article on the tog, one tog equals 0.1 square metre kelvin per watt, and the unit was created in 1946 at the Shirley Institute in Manchester. The test behind it is set out in the British Standard BS 4745. Our guide to how tog ratings are measured explains the test in detail.

The tog chart by season

Argos, Marks & Spencer and Primark each publish a seasonal tog guide, and Wikipedia gives its own comfort bands. They are close but not identical:

Sources: Argos, Marks & Spencer, Primark and Wikipedia, all checked on 5 October 2026.

The pattern is consistent. Summer duvets sit at 4.5 tog or below, spring and autumn duvets around 7.5 to 10.5, and winter duvets at 12 tog and above. Wikipedia notes that British duvets are sold in steps of 1.5 tog, from 3.0 tog for summer up to 16.5 tog for extra-warm.

Summer: 4.5 tog and below

Argos recommends 1 to 4.5 tog for summer, for "hot sleepers, warm bedrooms." A 4.5 tog duvet is the most common summer weight on sale. At Dunelm, it was the third most stocked rating when we checked, with 25 duvets listed.

If you sleep hot all year, a 4.5 tog can stay on the bed beyond summer. Our guide to the 4.5 tog summer duvet covers the lighter end of the range.

Spring and autumn: 7.5 to 10.5 tog

Argos says this band "can work year-round in mild homes." Marks & Spencer calls duvets between 7.5 and 10.5 tog "the middle of the road", best for transitional seasons like spring and autumn. At Dunelm, 7.5 tog was a common middle weight, with 20 duvets listed.

All season: 10.5 tog, or two duvets in one

There are two ways to cover the whole year.

One 10.5 tog duvet. Primark calls 10.5 tog "the most versatile and best year-round coverage," and Argos says all-season duvets "usually come in a 10.5 tog." It was also the most stocked rating at Dunelm, with 40 duvets listed.

A combined set. Marks & Spencer's All Seasons duvet is "a 3-in-1 combination of our 4.5 and 9 tog duvets", which you attach together for winter and separate for summer. Wikipedia describes the same idea: a 4.5 tog duvet for summer, a 9.0 tog duvet for spring and autumn, and both joined with press studs or Velcro to make a 13.5 tog duvet for winter. Bensons for Beds calls two duvets "the ideal solution for sleeping in a changing climate" if you have the budget and storage space.

Winter: 13.5 tog and up

Primark names 13.5 tog as "the best duvet for staving off chills in winter." The testing laboratory IDFL says 13.5 tog "is the most commonly used tog in Ireland and the UK", but adds that 12.0 and 10.5 tog duvets are becoming more popular as more homes have central heating. Bensons says that for most Brits, a duvet of "somewhere between 10.5 and 13.5 tog is the go-to."

A 15 tog duvet is for very cold rooms. IDFL describes 15.0 tog as "suitable for very cold winters", and Dunelm listed only 5 duvets at that weight. Our 13.5 tog winter duvet guide and our comparison of 13.5 tog and 15 tog duvets cover the warm end in detail.

Children's duvets: lower numbers

The adult chart does not apply to children. Argos gives separate guidance:

Babies are lower again. IDFL says a first-size baby sleeping bag in winter should not be more than 4 tog, and gives 18 °C as the ideal room temperature for a baby. Our children's duvet tog guide goes through each age in more detail.

Why one duvet rarely suits the whole year

Bensons explains the problem with a single duvet in the UK. A 13.5 tog duvet "can be difficult to live with in the height of summer when temperatures can suddenly shoot up to 30°C or even more," while in winter "a typically cosy 10.5 tog duvet barely takes the chill off a freezing night in the minus numbers." That is the case for either a combined set or two separate duvets.

What the chart does not tell you

The tog number is useful, but it has limits that the chart cannot show.

The label is a minimum. Bensons says the stated rating "is generally a minimum, meaning that the duvet inside could, in fact, have a rating of up to three togs higher." Wikipedia says the same.

Thicker is not always warmer. Primark notes that "synthetic fillings often require more material to match the insulation of a down duvet," so a synthetic duvet can be heavier than a down one with the same tog. Argos makes the same point: the tog does not describe the duvet's weight.

The test uses a new duvet. IDFL points out that ratings are measured on "a new quilt on a flat surface", and that poor-quality duvets lose warmth over time, especially after washing. It calls the tog "at best only a rough guide."

How to pick your number

1. Start with your bedroom. Primark says the right tog "depends on the temperature of the room you're sleeping in and how warm you like to feel." A cold room or a cold sleeper points up the chart; a warm room or a hot sleeper points down.
2. Decide between one duvet or two. A 10.5 tog covers most of the year in one purchase. A 4.5 plus 9 tog set covers every season but needs storage space.
3. Allow for the margin. Because the real figure can be higher than the label, a hot sleeper caught between two ratings may want the lower one.

Where to buy

The retailers whose guides appear above all sell duvets across the tog range: Dunelm (filterable by tog), Argos, Marks & Spencer, Primark and Bensons for Beds. For brand comparisons, see our Silentnight vs Slumberdown review.

For where the word "tog" comes from, and why it means swimwear in Australia and New Zealand, see what does togs mean.

References

• Argos: Duvet and pillow guide
• Marks & Spencer: Duvet buying guide
• Primark: Duvet tog guide
• Bensons for Beds: What is a duvet tog and which tog do I need?
• IDFL: TOG ratings explanation
• Wikipedia: Tog (unit)
• Dunelm: Duvets