How heavy should a weighted blanket be? The arithmetic, with real UK blankets

What is the 10% rule for a weighted blanket?

The 10% rule says a weighted blanket should weigh no more than a tenth of the person under it. The Royal College of Occupational Therapists (RCOT) guide says makers' instructions "usually say a weighted blanket shouldn't be more than 10% of the person's weight". Dunelm says approximately 10%. Sensory Direct says not to exceed 10%.

Notice the word. It is a ceiling more often than a target. Emma Sleep is the one maker we checked that gives a range, 8 to 10%.

How do you work out the right weight?

Divide your body weight in kilos by ten, then round down to the nearest weight the maker sells.

Sensory Direct publishes this logic on its Classic blanket page as a table of minimum body weights: 45kg for the 4.5kg blanket, 60kg for 6kg, 70kg for 7kg and 80kg for 8kg. If you are between sizes, it is the lower one that stays inside the rule.

What if you only know your weight in stone?

Convert to kilos first, because every maker here quotes the blanket in kilos. One stone is about 6.35kg. So 10 stone is about 63.5kg and a ceiling of 6.35kg, and 12 stone is about 76kg and a ceiling of 7.6kg. In both cases the practical answer is the lower whole weight on sale: 6kg and 7kg.

Do the sum with your actual weight, not the weight you are aiming for. If you are likely to move a stone either way over the year, pick the lower of the two ceilings.

Why do some blankets not fit the rule?

Because some makers sell a single weight, and a single weight only fits one band of people.

Dunelm sells one 7kg blanket. By the 10% rule it suits someone of 70kg or more. If you weigh 55kg, it is about 13% of your weight.

Emma's page is more awkward. It says 8 to 10% of body weight and a suitable adult range of 55 to 80kg. Work that through and the 7kg blanket fits 70kg (at 10%) up to about 87kg (at 8%). The 55 to 80kg range does not match. We cannot tell which figure is intended, so if you are under 70kg, ask Emma, or choose a blanket with more weights on offer. The same applies to the 13.5kg option, which by the same sum would suit someone of about 135kg.

Does body size, not just weight, change the answer?

Yes, because the blanket also has to physically cover you without hanging off the bed.

The Dunelm and Emma blankets are 150 by 200cm. The Sensory Direct Classic is 138 by 106cm. A narrow or short blanket puts the same weight on less of you. RCOT's guide adds that if one is used at night, it should not hang over the sides of the bed.

Dunelm also says not to fold its blanket in half to double the weight. The weight is meant to be spread over the blanket, not stacked.

How do you check a blanket against the rule before buying?

Write down three numbers: your weight in kilos, the blanket's weight, and the blanket's weight divided by yours. If the last one is above 0.10, the blanket is over the ceiling. A 7kg blanket for a 65kg person comes out at 0.108, which is just over; a 6kg blanket comes out at 0.092, which is inside. Then check the size against the bed and the returns terms against how sure you are.

What about warmth?

Weight holds fabric against your body, so it can feel warmer than a blanket of the same fabric without weight. The makers' pages we read gave no temperature ratings, and we did not find a tog rating on any of them. Cover fabric is the lever you have: Emma uses cotton, Dunelm a polyester microfibre, and Sensory Direct an OEKO-TEX certified polycotton. If you run warm, a lap pad puts weight on you without covering you.

When is a lighter weight a better answer?

When you are new to it, or when the person under it cannot easily lift it off.

RCOT's guide says a blanket should be chosen following the maker's instructions on weight and size, and that anyone needing a different weight should have the reason recorded. For children, adults who may struggle to remove the blanket, and anyone with a health condition, that is a conversation to have with an occupational therapist or your GP. Sensory Direct's page also advises consulting an occupational therapist about weight.

Things to know

• A guide, not a prescription. The 10% figure comes from makers and RCOT. We make no claim that any weight works better than another for any person.
• Children. The same 10% ceiling applies, but the safety rules matter more than the sum. See our guide on weighted items and children.
• What we could not confirm. None of the makers say whether the stated weight includes the cover, and we found no tog ratings. Emma's weight range and percentage do not match, as above.
• We have not tested these. The figures are from the makers' pages and RCOT's guide, checked on 20 October 2026.