A weighted blanket calculator applies one piece of arithmetic — a percentage of body weight — and then, if you are making rather than buying, divides the filling across a sewn grid. Both halves are simple. What is not simple is the percentage itself, which is repeated across the entire internet as though it were an established standard and is not one. This page does the arithmetic and tells you exactly what the number is and where it came from, because a figure you can trace is worth more than a figure you cannot.
Before any of that: this page carries a safety section, and it is placed before the maths rather than after it for a reason. Weighted blankets have caused deaths. Arb Digital publishes free calculators across hundreds of everyday topics, and where a calculation touches a documented physical hazard, the hazard is stated plainly rather than tucked into a footer.
Safety First, and Not as a Formality
A weighted blanket is heavy fabric that a person is underneath. That is the whole hazard in one sentence. The risks are entrapment — becoming caught inside or under it — and suffocation, and they apply to anyone who cannot remove the blanket without help.
Not for infants or toddlers. The NIH Safe to Sleep campaign states that there is not enough evidence that weighted blankets and swaddles are safe for babies, and that both the Consumer Product Safety Commission and the American Academy of Pediatrics advise parents not to use them. The stated concerns include a developing ribcage that must expand to breathe, added weight preventing a baby who has rolled from rolling back, and overheating.
Not for anyone who cannot lift it off unaided. This is the general form of the same rule and it extends well past infancy. It covers young children, anyone with limited strength or mobility, anyone who cannot reliably call for help, and anyone who might become confused or disoriented at night. If there is any doubt about whether a person could get out from under it on their own, the answer is no.
Check the manufacturer's limits. Commercial blankets carry stated minimum ages and weights. Those limits are set for that specific product and override any percentage this or any other calculator produces. Weighted products for children have been recalled after fatal incidents; the age labelling on a product exists because of that history.
This page also makes no health claim of any kind. It does not present a weighted blanket as a treatment for anxiety, insomnia, sensory processing differences or any other condition, and no result it produces should be read that way. It reports weight in pounds and grams. That is the entire scope.
What This Weighted Blanket Calculator Does
It takes an adult body weight and a percentage, multiplies them, and reports the resulting blanket weight in both pounds and kilograms, alongside the nearest size that is commonly sold. Because retail sizes come in fixed steps, the calculated figure and the purchasable figure are rarely the same number, and it is more useful to see both.
The second half is for people sewing their own. Given the blanket's dimensions and the pocket size you plan to sew, it works out how many pockets the grid contains, subtracts the fabric and thread weight from the target so the finished item hits the number rather than overshooting it, and divides the remaining filling weight evenly across the pockets in grams. That per-pocket figure is what you actually weigh out at the table.
How to Use It
- Read the safety section above first. If the person the blanket is for cannot lift it off unaided, stop here — the arithmetic below does not apply to them.
- Enter the adult body weight. The percentage convention is defined against body weight, so this is the input that drives everything.
- Set the percentage. 10% is the default because it is the figure in circulation. It is adjustable because it is a convention, not a measurement.
- Enter the blanket dimensions and pocket size. Only needed if you are sewing. A weighted blanket is normally sized to the person rather than to the bed, so that it does not hang over the sides.
- Weigh out the per-pocket figure. Use a kitchen scale in grams. Eyeballing the filling by volume produces a blanket that is heavy at one end.
The Formula — How It's Calculated
The blanket weight is body weight × percentage ÷ 100. Everything else follows from the blanket's geometry.
The pocket grid is the width divided by the pocket size, rounded down, times the length divided by the pocket size, rounded down. Rounding down matters: a 48-inch width with 5-inch pockets gives 9.6, and you cannot sew six tenths of a pocket, so the grid is 9 columns and the remainder becomes seam allowance and edging.
The filling weight is the target blanket weight minus the fabric and thread weight, and the per-pocket figure is that filling weight divided by the pocket count, converted to grams because kitchen scales are accurate at that scale and imprecise in ounces.
Worked example, using the values the page loads with. A 160 lb adult at 10% gives a target blanket weight of 16.0 lb, which is 7.26 kg. The nearest commonly sold size is 15 lb. A 48 × 72 inch blanket with 5-inch pockets gives 48 ÷ 5 = 9.6 → 9 columns, and 72 ÷ 5 = 14.4 → 14 rows, so 126 pockets. Subtracting 1.5 lb of fabric and thread leaves 14.5 lb of filling, which is 6,577 grams, so each pocket takes 6,577 ÷ 126 = 52.2 grams.
Where the 10% Figure Actually Comes From
This is the part worth knowing, because the figure is quoted with far more authority than its origin supports.
The 10% target did not originate with blankets. It came from occupational-therapy practice with weighted vests, where a vest weight of approximately 10% of body weight was a common recommendation, and it was subsequently carried across to blankets by researchers and manufacturers. A 2023 paper in Occupational Therapy International sets this out directly: the vest weight is often recommended at approximately 10% of body weight, and some weighted-blanket research has used that same 10% target. The same paper notes that the evidence supporting weighted vests is itself limited.
The authors also make an observation that undercuts the transfer entirely: a vest covers only the torso and is typically worn while upright, whereas a blanket covers the whole body while lying down. Those are different loading situations, and there is no obvious reason a percentage tuned for one should be correct for the other. Investigation of what blanket weight in relation to body weight would actually be appropriate is described as work that would improve the recommendation — which is to say, it has not been settled.
So the honest description of the 10% rule is this: it is a borrowed convention with a traceable but weak origin, and it is not a clinical standard. It is a reasonable starting point precisely because it is common, which makes products and instructions consistent with each other, and for no stronger reason than that. The percentage field on this page is editable for exactly that reason.
Why Retail Sizes Never Match the Calculation
Weighted blankets are manufactured in fixed steps — commonly 5, 7, 10, 12, 15, 20 and 25 pounds — because production runs at a small number of fill weights rather than a continuous range. Your calculated figure will almost always fall between two of them.
The gap is proportionally largest at the ends of the range. Someone whose calculation lands at 22 lb is choosing between 20 and 25, a step of five pounds on a target of twenty-two — a swing of over 20% either way. That is a much bigger deviation than the difference between a 9% and an 11% convention, which tells you something useful about how much precision the percentage really carries. The weight converter and the kg to pounds converter handle the unit side if you are comparing products listed in different systems.
Filling, Pockets and Why the Grid Matters
The filling is what makes the arithmetic real. Glass microbeads are the most common modern choice because they are dense, so a given weight takes up less volume and the blanket stays thinner. Plastic poly pellets are larger for the same weight and produce a bulkier blanket. Dry goods such as rice or beans are sometimes suggested and are a poor idea in anything intended to last, because they cannot be washed and will eventually spoil.
Pocket size is the variable most home sewers get wrong. Large pockets are much faster to sew and let the filling shift within each square, so the weight pools wherever gravity takes it and the blanket ends up heavy at the feet. Five-inch squares are a common compromise. Smaller squares distribute better and multiply the sewing time, since the number of pockets goes up with the square of the reduction — halving the pocket size quadruples the count.
Sizing is the other common error. A weighted blanket is sized to the person, not the bed. If it hangs over the mattress edge, the overhanging portion pulls the rest of the blanket off with it, and the weight ends up on the floor rather than on the person. Standard bedding dimensions are the wrong starting point. If you are working out material quantities, the fabric yardage calculator and the quilt fabric calculator cover the cutting side, and the grams to ounces converter is useful when a filling is sold in one unit and your scale reads the other.
Arb Digital's free tools library covers hundreds of everyday calculations, and our team is happy to talk through anything the tools cannot answer.
Browse Free Tools Talk to Arb DigitalCommon Mistakes to Avoid
- Using an adult convention for a child — the percentage rule was borrowed from adult vest practice, and weighted products carry documented hazards for young children.
- Treating 10% as a standard — it is a convention carried over from weighted vests, and the paper that traces it also notes the vest evidence is limited.
- Sizing the blanket to the bed — overhang drags the weight off the mattress and takes the rest of the blanket with it.
- Filling pockets by eye — small differences compound across a hundred-plus pockets and the blanket ends up heavier at one end.
- Forgetting the fabric weight — filling to the target weight and then adding the fabric makes the finished blanket heavier than intended.
Related Free Tools From Arb Digital
Use the weight converter for pounds, kilograms and grams, the kg to pounds converter when comparing products listed in different units, the grams to ounces converter for filling weighed on a kitchen scale, the fabric yardage calculator for how much material to buy, and the quilt fabric calculator for the cutting plan on a sewn grid. Everything else is in the free online tools hub.
Frequently Asked Questions
From occupational-therapy practice with weighted vests, where roughly 10% of body weight was a common vest recommendation, and it was later carried across to blankets. A 2023 paper in Occupational Therapy International documents that transfer and notes that the evidence for weighted vests is itself limited.
No. It is a convention with a traceable but weak origin. A vest covers the torso and is worn upright while a blanket covers the whole body lying down, and there is no established reason a percentage tuned for one should be right for the other.
The NIH Safe to Sleep campaign states there is not enough evidence that weighted blankets are safe for babies, and that the Consumer Product Safety Commission and the American Academy of Pediatrics advise against them. Beyond infancy, the manufacturer's stated age and weight limits govern, and no calculator overrides them.
Anyone who cannot lift it off themselves without help. That includes infants and toddlers, and it extends to anyone with limited strength or mobility, anyone who could not reliably call for help, and anyone who might become disoriented at night.
This page makes no claim of that kind and cannot assess one. It calculates weight in pounds and grams. Any question about managing a health condition belongs with a doctor or a qualified occupational therapist.
Sized to the person rather than to the bed. A blanket that hangs over the mattress edge lets the overhanging weight pull the rest of it onto the floor, so standard bedding dimensions are the wrong starting point.
Glass microbeads are dense, so a given weight occupies less volume and the blanket stays thinner. Poly pellets are bulkier for the same weight. Rice and beans cannot be washed and will eventually spoil, so they are unsuitable for anything meant to last.
The calculator shows the nearest commonly sold size so you can see the gap. The step between retail sizes is often larger than the difference a couple of percentage points would make, which is a fair indication of how much precision the convention carries.
This tool performs arithmetic on weights and dimensions you enter. It is not medical advice, it does not recommend a weighted blanket for anyone or for any purpose, and it makes no claim that one treats any condition. Weighted blankets present documented entrapment and suffocation hazards; they must never be used for infants or toddlers or for anyone unable to remove one unaided, and the manufacturer's age and weight limits always take precedence. Any health question should go to a doctor or a qualified occupational therapist.
