GSM Converter (Paper & Fabric Weight)
gsm ↔ pounds for every US paper grade, fabric oz/yd², thickness and ream weight.
Type a weight in plain words — “20 lb bond to gsm”, “300 gsm to lb cover”, “80# text in g/m²”, “14 oz/yd² to gsm” — or use the boxes below.
Rounded · lb bond ≈ g/m² × 0.2659765198 · 1 g/m² ≈ 0.2659765198 lb bond
- Grams per square metre, gsm: grammage, the mass of one square metre (ISO 536); “gsm” and “g/m²” are the same thing
- Bond, writing & copy paper: the weight in pounds of 500 sheets of bond or writing paper 17 × 22 in; 1 lb = 3.7597 g/m²
Thickness and density
Uses the weight in the converter above: thickness (µm) = grammage (g/m²) ÷ density (g/cm³). The same weight can be thin and dense or thick and bulky.
From the average thicknesses in the US government paper standards (table below).
Type a density, or choose an example paper.
Sheet and ream weight
Uses the weight in the converter above: one sheet weighs grammage × sheet area.
Empty: a ream of 500.
Pick a sheet size.
Fabric by the running yard or metre
Fabric sold by length weighs its weight per area × its width, so the same cloth is heavier per yard on a wider roll.
Type the fabric’s width.
80 g/m² in every unit
Select a unit to convert to it. Values marked ≈ are rounded; all others are exact.
| Unit | Value | Copy |
|---|---|---|
| Metric | ||
| from | 80 | |
| Fabric | ||
| ≈ 2.359481975 | ||
| US paper basis weight (lb per 500 sheets) | ||
| to | ≈ 21.27812159 | |
| ≈ 54.04870457 | ||
| ≈ 29.58455408 | ||
| ≈ 36.48287558 | ||
| ≈ 44.24882103 | ||
| ≈ 49.15587447 | ||
| ≈ 49.15587447 | ||
| US board (lb per area) | ||
| ≈ 16.38529149 | ||
Convert a list of values
Up to 1,000 lines. Fractions (3/4), mixed numbers (1 1/2) and grouped digits (1,250) are fine.
| Value | Result |
|---|
Paper weight equivalents
The same paper in each grade’s pounds. Values marked ≈ are rounded to 6 significant digits.
US weights in g/m² and other grades
| Weight | g/m² | lb bond | lb text | lb cover | lb index |
|---|---|---|---|---|---|
| 20 lb bond | ≈ 75.1946 | 20 | ≈ 50.8021 | ≈ 27.8075 | ≈ 41.5909 |
| 24 lb bond | ≈ 90.2335 | 24 | ≈ 60.9626 | ≈ 33.369 | ≈ 49.9091 |
| 28 lb bond | ≈ 105.272 | 28 | ≈ 71.123 | ≈ 38.9305 | ≈ 58.2273 |
| 32 lb bond | ≈ 120.311 | 32 | ≈ 81.2834 | ≈ 44.492 | ≈ 66.5455 |
| 50 lb text | ≈ 74.0073 | ≈ 19.6842 | 50 | ≈ 27.3684 | ≈ 40.9342 |
| 60 lb text | ≈ 88.8088 | ≈ 23.6211 | 60 | ≈ 32.8421 | ≈ 49.1211 |
| 70 lb text | ≈ 103.61 | ≈ 27.5579 | 70 | ≈ 38.3158 | ≈ 57.3079 |
| 80 lb text | ≈ 118.412 | ≈ 31.4947 | 80 | ≈ 43.7895 | ≈ 65.4947 |
| 100 lb text | ≈ 148.015 | ≈ 39.3684 | 100 | ≈ 54.7368 | ≈ 81.8684 |
| 65 lb cover | ≈ 175.767 | 46.75 | 118.75 | 65 | 97.21875 |
| 80 lb cover | ≈ 216.329 | ≈ 57.5385 | ≈ 146.154 | 80 | ≈ 119.654 |
| 100 lb cover | ≈ 270.411 | ≈ 71.9231 | ≈ 182.692 | 100 | ≈ 149.567 |
| 110 lb index | ≈ 198.875 | ≈ 52.8962 | ≈ 134.362 | ≈ 73.5455 | 110 |
| 140 lb index | ≈ 253.114 | ≈ 67.3224 | ≈ 171.006 | ≈ 93.6033 | 140 |
Metric weights in US grades
| Weight | lb bond | lb text | lb cover | lb index | oz/yd² |
|---|---|---|---|---|---|
| 60 g/m² | ≈ 15.9586 | ≈ 40.5365 | ≈ 22.1884 | ≈ 33.1866 | ≈ 1.76961 |
| 70 g/m² | ≈ 18.6184 | ≈ 47.2926 | ≈ 25.8865 | ≈ 38.7177 | ≈ 2.06455 |
| 80 g/m² | ≈ 21.2781 | ≈ 54.0487 | ≈ 29.5846 | ≈ 44.2488 | ≈ 2.35948 |
| 90 g/m² | ≈ 23.9379 | ≈ 60.8048 | ≈ 33.2826 | ≈ 49.7799 | ≈ 2.65442 |
| 100 g/m² | ≈ 26.5977 | ≈ 67.5609 | ≈ 36.9807 | ≈ 55.311 | ≈ 2.94935 |
| 120 g/m² | ≈ 31.9172 | ≈ 81.0731 | ≈ 44.3768 | ≈ 66.3732 | ≈ 3.53922 |
| 160 g/m² | ≈ 42.5562 | ≈ 108.097 | ≈ 59.1691 | ≈ 88.4976 | ≈ 4.71896 |
| 200 g/m² | ≈ 53.1953 | ≈ 135.122 | ≈ 73.9614 | ≈ 110.622 | ≈ 5.8987 |
| 250 g/m² | ≈ 66.4941 | ≈ 168.902 | ≈ 92.4517 | ≈ 138.278 | ≈ 7.37338 |
| 300 g/m² | ≈ 79.793 | ≈ 202.683 | ≈ 110.942 | ≈ 165.933 | ≈ 8.84806 |
| 350 g/m² | ≈ 93.0918 | ≈ 236.463 | ≈ 129.432 | ≈ 193.589 | ≈ 10.3227 |
Thickness of US government paper grades
Average thickness from the U.S. Government Paper Specification Standards (Part 5); g/m² and density are worked out from it. Papers of the same weight from other mills differ: a maker’s data sheet gives the thickness of its own paper.
| Grade | Basis weight | g/m² | mil | µm | g/cm³ |
|---|---|---|---|---|---|
| Newsprint JCP A15 | 30 lb newsprint | 48.82 | 3 | 76.2 | 0.641 |
| Bond JCP G10 | 20 lb bond | 75.19 | 3.7 | 93.98 | 0.8 |
| Plain copier paper JCP O-65 | 20 lb bond | 75.19 | 4 | 101.6 | 0.74 |
| Uncoated text JCP A60 | 60 lb text | 88.81 | 4.7 | 119.4 | 0.744 |
| Matte-coated text JCP A240 | 80 lb text | 118.4 | 4.9 | 124.5 | 0.951 |
| Gloss-coated text JCP A180 | 80 lb text | 118.4 | 3.6 | 91.44 | 1.29 |
| Uncoated cover JCP L23 | 65 lb cover | 175.8 | 7.5 | 190.5 | 0.923 |
| Gloss-coated cover JCP L10 | 80 lb cover | 216.3 | 8.1 | 205.7 | 1.05 |
| Vellum bristol cover JCP L24 | 67 lb bristol | 146.9 | 8.3 | 210.8 | 0.697 |
| Index JCP K10 | 110 lb index | 198.9 | 9 | 228.6 | 0.87 |
| High-finish manila tag JCP P10 | 150 lb tag | 244.1 | 11.4 | 289.6 | 0.843 |
About the GSM Converter (Paper & Fabric Weight)
Convert the weight of paper, card and fabric between grams per square metre (gsm, g/m²), the US basis weights of bond, text, cover, bristol, index, tag and newsprint, ounces per square yard and pounds per 1,000 ft². Type in either box and the other updates; the table shows the weight in every unit, and Quick convert reads text such as 20 lb bond to gsm or 300 gsm to lb cover. Every conversion is exact.
Under the converter, work out a sheet’s thickness from its density (or its density from a measured thickness, with pages per inch for book spines), the weight of one sheet, a ream or 1,000 sheets of any size, and how much fabric weighs per running yard or metre at its width.
How to use it
- Type the weight in From and pick its unit — or type
80# cover in gsmin Quick convert and press Enter — then pick the unit you want in To. - Read the result and the table of every unit; the line under the result gives the weight of one A4 and one US Letter sheet.
- For thickness, type the paper’s density (or pick an example) under Thickness and density, or switch to Thickness and type a measured caliper.
- Pick a sheet size under Sheet and ream weight for the weight of one sheet, the pack and 1,000 sheets; type a fabric width for the weight per running yard.
- Copy the result or a link, download the table as CSV, or convert a list of weights under Convert a list of values.
Examples
20 lb bond to gsm
≈ 75.19 g/m²
The same paper is about 50.8 lb text: a pound means a different sheet size in each grade.
80 lb cover to gsm
≈ 216.3 g/m²
300 gsm to lb cover
≈ 110.9 lb cover
80 g/m² to lb text
≈ 54.05 lb text (21.28 lb bond)
14 oz/yd² to gsm
≈ 474.7 g/m²
1 oz/yd² = 28.349523125 g ÷ 0.83612736 m² ≈ 33.906 g/m².
80 g/m², A4, 500 sheets
4.99 g a sheet, 2.495 kg a ream
An A4 sheet is 0.06237 m².
80 g/m² at 0.8 g/cm³
100 µm (3.94 mil), about 508 pages per inch
Common uses
- Matching a European paper or card in g/m² to a US weight in pounds, or the other way round.
- Comparing card stocks sold as cover, index or bristol.
- Working out postage weight of a mailing from the paper weight and sheet size.
- Finding pages per inch for a book spine from the paper’s thickness.
- Converting fabric weight between oz/yd² and g/m², and pricing fabric by the running yard.
Why “20 lb” depends on the grade
A US basis weight is the weight in pounds of 500 sheets of the grade’s basis size, and each grade has its own size, as in the U.S. Government Paper Specification Standards:
- Bond, writing and copy paper: 17 × 22 in — 1 lb ≈ 3.760 g/m²
- Book, text and offset: 25 × 38 in — 1 lb ≈ 1.480 g/m²
- Cover: 20 × 26 in — 1 lb ≈ 2.704 g/m²
- Bristol: 22½ × 28½ in — 1 lb ≈ 2.193 g/m²
- Index: 25½ × 30½ in — 1 lb ≈ 1.808 g/m²
- Tag and newsprint: 24 × 36 in — 1 lb ≈ 1.627 g/m²
So 20 lb bond (75.2 g/m²) is the same paper as about 50.8 lb text. Grammage, the mass of one square metre (ISO 536), needs no grade, which is why it is the easiest way to compare papers.
Thickness, density and bulk
thickness (µm) = grammage (g/m²) ÷ density (g/cm³), and bulk (cm³/g) is 1 ÷ density. Weight alone does not fix thickness: in the US government standards, 20 lb bond averages 3.7 mil (94 µm), about 0.80 g/cm³, while 80 lb gloss-coated text, which weighs about 1.6 times as much, averages only 3.6 mil — about 1.30 g/cm³. The table under the converter lists eleven grades this way.
A mil is a thousandth of an inch (25.4 µm); board calipers in “points” (pt) use the same thousandth of an inch. Pages per inch (PPI) counts two pages to a sheet: PPI = 2 ÷ thickness in inches.
Sheet, ream and M weight
- One sheet = grammage × area: an A4 sheet (0.06237 m²) of 80 g/m² weighs 4.99 g.
- A pack = one sheet × sheets in it: 500 sheets of that A4 weigh 2.495 kg.
- M weight is the US weight of 1,000 sheets of a given size, in pounds: 11.0 lb for that A4 paper.
For the basis size itself, 500 sheets weigh exactly the basis weight — a quick check of any figure.
Fabric weight
Fabric weight per area is given in g/m² or oz/yd² (1 oz/yd² ≈ 33.906 g/m², from the exact ounce and yard; NIST SP 811 lists 3.390 575 × 10⁻² kg/m²). Fabric sold by length is sometimes weighed per running (linear) yard instead, which depends on the width: 10 oz/yd² at 58 in wide is 10 × 58 ÷ 36 ≈ 16.1 oz per running yard.
Test methods: ISO 536 for the grammage of paper and board; TAPPI T 410 and ASTM D646 for grammage and basis weight; ASTM D3776 for the mass per unit area of fabric.
Limitations
- Thickness comes from the density you give: papers of the same weight differ, so use the maker’s data sheet or a measured caliper when it matters.
- Basis weights are nominal: mills make paper within a tolerance of the stated weight.
- Ounces per running yard depend on the fabric width, so they are worked out in their own panel rather than converted.
- A ream is taken as 500 sheets unless you type another count.
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Frequently asked questions
How many gsm is 20 lb paper?
20 lb bond (copy and writing paper) is 75.2 g/m². The grade matters: 20 lb text would be only 29.6 g/m², because text weight is counted on a larger sheet. 24 lb bond is 90.2 g/m² and 28 lb bond 105.3 g/m².
Is 80 gsm the same as 20 lb?
Close but not equal: 80 g/m² is 21.3 lb bond, and 20 lb bond is 75.2 g/m². In text weight, 80 g/m² is about 54 lb.
What is the difference between text weight and cover weight?
Only the sheet the pounds are counted on: text (book, offset) uses 500 sheets of 25 × 38 in and cover 500 sheets of 20 × 26 in. So 80 lb cover (216 g/m²) is much heavier than 80 lb text (118 g/m²).
How thick is 300 gsm card?
It depends on its density: at 1.0 g/cm³ it is 300 µm (11.8 mil or pt); a bulkier uncoated board at 0.8 g/cm³ is 375 µm. Type the weight above and a density, or a measured thickness, under Thickness and density.
What does M weight mean?
The weight in pounds of 1,000 sheets of a particular size. For 80 g/m² A4 it is 11.0 lb; the sheet and ream panel gives it for any size and weight.
How do I convert oz/yd² to gsm?
Multiply by 33.906: 1 oz/yd² = 28.349523125 g on 0.83612736 m². So 8 oz/yd² ≈ 271 g/m² and 14 oz/yd² ≈ 475 g/m²; divide by 33.906 for the other way.