What Tog Duvet Do You Need? A UK Guide to Duvet Tog Ratings

By Snoozyn · Updated September 2026

Duvets in the UK are sold by tog, and the numbers run from about 1 to 15. This guide explains what the rating actually measures, what each common tog is usually bought for, and the three things people often confuse with it: weight, fill and size.

What does tog mean?

Tog is a British unit of thermal resistance, devised in the 1940s at the Shirley Institute in Manchester. It describes how well a textile holds in heat. One tog equals 0.1 square metre kelvin per watt, but you never need the formula: a higher tog simply means more insulation, and a lower tog means less.

The tog on the label is measured on the duvet itself. It tells you about the duvet, not about the room, the mattress or the person under it.

Duvet tog ratings at a glance

These are the conventions most UK retailers use, not rules. Two households with the same 10.5 tog duvet can reach different conclusions about it, because bedrooms differ so much.

How to choose the right tog

Start with the bedroom

Think about how warm the room is in January and in July. A well-insulated flat with the heating on overnight is a different place from an older house with the heating off, and the right tog follows the room.

Decide between one duvet or two

If you want one duvet on the bed all year, 10.5 tog is the usual pick. If you would rather change with the seasons, a 4.5 tog for summer and a 13.5 tog for winter is the common pair. Some duvets are sold as combination sets, typically a 4.5 and a 9 tog that fasten together to make 13.5.

Sharing a bed

Two people who prefer different weights can use two single duvets on one bed, each in its own cover. It is a common arrangement in much of Europe.

Tog is not weight, and it is not the fill

A higher tog does not have to mean a heavier duvet. Different fills reach the same tog at different weights: down is light for its tog, while coarse synthetic hollowfibre needs more bulk to get there. So compare tog with tog, and look at the weight separately if you prefer a lighter or heavier feel on the bed.

For reference, here are the weights of our own 10.5 tog insert.

What goes inside ours

Our All-Season Duvet Insert is 100% polyester: micro-denier fibre clusters inside a soft microfibre shell. The fibres are crimped into three-dimensional clusters that recover their loft after being compressed, and the fill is held in quilted chambers across the whole insert so it cannot drift to one end. It has no feathers and no quills. Like all our inserts it is synthetic, and we say so plainly on the product page.

Get the size right as well as the tog

The duvet must match its cover. A duvet that is too small leaves empty corners in the cover; one that is too big bunches up inside it. Our inserts are cut to the same sizes as our duvet covers, and each has eight perimeter loops that tie to the ties inside every Snoozyn cover, so it stays square.

UK duvet sizes are not the same as continental ones. Our UK bed sizes guide lists every duvet, sheet and pillowcase size by bed. If you need a continental size such as 140 × 200 or 220 × 220 cm, we make those to order through custom sizes.

Caring for a duvet so the tog lasts

A duvet that has gone flat has lost loft, and loft is where the insulation comes from. Keep it in a cover, wash the cover weekly with your sheets and wash the duvet itself only two or three times a year. Ours goes in the machine on a cool, gentle cycle and then in the tumble dryer on low until it is completely dry; a couple of dryer balls bring the loft back. How often to wash each piece is in our guide to how often to change your bed sheets, and the full routine is in the care guide.

Our 10.5 tog insert costs £64.90 for a Single, £79.90 for a Double, £94.90 for a King and £109.90 for a Super King.

Questions people ask about duvet togs

What tog duvet is best for the UK?

A 10.5 tog duvet is the most common single choice for year-round use in a UK home. Households that like a lighter duvet in summer often keep a 4.5 tog as well, and some move up to 13.5 tog for the coldest months.

What does tog mean on a duvet?

Tog is a British unit that measures how well a duvet holds in heat, known as its thermal resistance. One tog equals 0.1 square metre kelvin per watt. The higher the tog, the more insulation the duvet gives.

Is a 10.5 tog duvet too warm for summer?

That depends on your bedroom and on how you like to sleep. Many people use a 10.5 tog duvet all year round, while others swap to a 4.5 tog for July and August. The tog figure describes the duvet, not the room.

Does a higher tog mean a heavier duvet?

Not necessarily. Tog measures insulation, not weight, and different fills reach the same tog at different weights. Our 10.5 tog double weighs about 1.40 kg.

What tog is the Snoozyn duvet insert?

Our All-Season Duvet Insert is 10.5 tog. It is filled with micro-denier polyester clusters held in quilted chambers, and comes in Single, Double, King and Super King.

Can you wash a 10.5 tog duvet at home?

Ours can be. Machine wash it cool on a gentle cycle, then tumble dry on low until it is completely dry. A couple of dryer balls help bring the loft back.