LBS to GSM & GSM to LBS Converter
Convert paper weight between U.S. basis weight and GSM. Select the paper category first because lb-to-GSM results change by paper type.
Enter a value to see the formula.
This conversion is approximate.
| Paper Category | Formula | Approx. Result |
|---|
Try common paper weight conversions or compare the same value across different paper types.
This calculator converts paper weight, not paper thickness. Use the result as a reference only, and confirm the actual paper grade, caliper, stiffness, and sample before production.
Formula factors are based on the standard U.S. basis size for each paper category.
| Paper Category | Basis Size | LBS to GSM | GSM to LBS | Common Use |
|---|---|---|---|---|
| Bond | 17 × 22 in | lb × 3.76 | gsm ÷ 3.76 | Office paper, letterheads |
| Text / Book | 25 × 38 in | lb × 1.48 | gsm ÷ 1.48 | Booklets, brochures, catalogs |
| Cover | 20 × 26 in | lb × 2.708 | gsm ÷ 2.708 | Cards, covers, tags, inserts |
| Index | 25.5 × 30.5 in | lb × 1.81 | gsm ÷ 1.81 | Index cards, dividers |
| Bristol | 22.5 × 28.5 in | lb × 2.19 | gsm ÷ 2.19 | Cards, tags, display pieces |
| Tag | 24 × 36 in | lb × 1.63 | gsm ÷ 1.63 | Hang tags, labels, retail tags |
GSM to LBS Conversion Chart
Use this GSM to LBS conversion chart to compare common paper weights across cover and text paper categories. For cards, hang tags, covers, and packaging inserts, the cover lb column is usually the most useful. For brochures, books, catalogs, and flyers, the text lb column is usually more relevant.
| GSM | Approx. Cover lb | Approx. Text lb | Typical Use / Feel |
|---|---|---|---|
| 100 gsm | 37 lb cover | 68 lb text | Light documents, forms |
| 120 gsm | 44 lb cover | 81 lb text | Premium documents, light flyers |
| 150 gsm | 55 lb cover | 101 lb text | Flyers, brochures |
| 170 gsm | 63 lb cover | 115 lb text | Heavy flyers, light card |
| 180 gsm | 67 lb cover | 122 lb text | Light cardstock |
| 200 gsm | 74 lb cover | 135 lb text | Thin card, covers |
| 216 gsm | 80 lb cover | 146 lb text | Close to 80 lb cover |
| 230 gsm | 85 lb cover | 155 lb text | Medium card |
| 250 gsm | 92 lb cover | 169 lb text | Postcards, inserts |
| 300 gsm | 111 lb cover | 203 lb text | Cards, tags, covers |
| 350 gsm | 129 lb cover | 236 lb text | Thick cards, premium tags, folding carton boxes |
| 400 gsm | 148 lb cover | 270 lb text | Very heavy card |
These values are approximate and may be rounded differently by suppliers. Use them for paper weight comparison only, not as exact thickness, stiffness, or packaging performance specifications.
LBS to GSM Conversion Chart
Use this LBS to GSM conversion chart when a paper specification is listed as bond, text, or cover weight. The same lb number can convert to different GSM values, so always check the paper category before comparing materials.
| Paper Weight | Approx. GSM | Typical Use |
|---|---|---|
| 20 lb Bond | 75 gsm | Standard copy paper |
| 24 lb Bond | 90 gsm | Better office paper, letterheads |
| 28 lb Bond | 105 gsm | Premium documents |
| 32 lb Bond | 120 gsm | Thick documents, presentations |
| 60 lb Text | 89 gsm | Booklets, manuals |
| 70 lb Text | 104 gsm | Flyers, inserts |
| 80 lb Text | ≈118–120 gsm | Brochures, flyers |
| 100 lb Text | 148 gsm | Premium text paper, catalog pages |
| 65 lb Cover | 176 gsm | Light cardstock |
| 80 lb Cover | 217 gsm | Cards, inserts, light tags |
| 100 lb Cover | 271 gsm | Cards, covers, hang tags |
| 110 lb Cover | 298 gsm | Premium cardstock |
| 130 lb Cover | 352 gsm | Thick cardstock, luxury print items |
These values are approximate. For production, confirm the final paper grade, caliper, coating, folding result, and physical sample before approval.
What Different GSM Paper Weights Mean
Different GSM values give paper a different feel, flexibility, and level of stiffness. Lower GSM paper is usually lighter and easier to fold, while higher GSM paper feels firmer, heavier, and more card-like.
| GSM Range | General Feel | Common Uses |
|---|---|---|
| 100–150 gsm | Flexible paper | Documents, forms, flyers, brochures, lightweight inserts |
| 180–200 gsm | Heavy paper / light card | Premium flyers, booklet covers, light cards, product inserts |
| 250–300 gsm | Medium to sturdy cardstock | Postcards, hang tags, product cards, packaging inserts, light sleeves |
| 300–350 gsm | Sturdy cardstock / light paperboard | Hang tags, backing cards, folding carton boxes, sleeves, premium inserts |
| 350 gsm+ | Thick cardstock / heavier paperboard | Premium cards, luxury tags, rigid inserts, stronger folding cartons |
Use GSM as a starting point, then confirm the actual paper grade, caliper, stiffness, and sample before production.
GSM vs LBS: Why Text Weight and Cover Weight Are Different
GSM and LBS both describe paper weight, but they use different measurement systems.
GSM is straightforward. It stands for grams per square meter, so 300 gsm means one square meter of that paper weighs 300 grams. Because GSM always uses the same area measurement, it is easier to compare across different paper types, boards, and packaging materials.
LBS is more complicated. In the U.S. paper system, lb usually refers to basis weight: the weight of 500 sheets in a specific standard parent sheet size. The confusing part is that different paper categories use different basis sizes.
That is why the same lb number can describe very different papers. Always confirm the paper category before converting LBS to GSM.
Text Weight vs Cover Weight
| Example | Approx. GSM | Typical Use |
|---|---|---|
| 80 lb Text | 118–120 gsm | Brochures, flyers, booklets |
| 80 lb Cover | 217 gsm | Cards, light tags, inserts |
| 100 lb Text | 148 gsm | Premium pages, catalogs, flyers |
| 100 lb Cover | 271 gsm | Cards, covers, hang tags |
Text weight paper is usually thinner, lighter, and more flexible, while cover weight paper is heavier, stiffer, and more suitable for cards, covers, hang tags, product cards, and packaging inserts. This is why “80 lb paper” or “100 lb paper” is not specific enough for accurate conversion. Choose the paper category before converting LBS to GSM; without that category, the result is incomplete.
Can You Convert GSM to mm, pt, or Paper Thickness?
Many people search for GSM to mm, GSM to pt, or pt to GSM conversion, but paper weight and paper thickness are not the same measurement.
GSM measures paper weight, while mm, pt, and caliper describe physical thickness. Millimeters show the physical thickness of a sheet, while points are commonly used for cardstock thickness. One point equals 0.001 inch.
For a deeper explanation of paper thickness, caliper, GSM, mm, pt, and packaging material selection, read our paper thickness guide.
This means there is no exact formula for converting GSM to mm or pt. A 300 gsm coated paper may feel smoother and thinner, while a 300 gsm high-bulk uncoated paper may feel thicker and softer. Paper density, coating, fiber structure, compression, moisture, and manufacturing process can all affect the final caliper.
Use the table below only as a rough reference.
| Paper Type | Common GSM | Rough Thickness |
|---|---|---|
| Copy paper | 75–90 gsm | About 0.09–0.12 mm |
| Flyer paper | 120–170 gsm | About 0.12–0.20 mm |
| Light cardstock | 200–250 gsm | About 0.22–0.30 mm |
| Cardstock / cover stock | 300–350 gsm | About 0.30–0.45 mm |
| Heavy card | 400 gsm+ | About 0.45 mm+ |
For example, 300 gsm tells you the paper weight, but it does not automatically tell you whether the paper is 0.30 mm, 0.35 mm, or 0.45 mm thick. If thickness matters for printing, folding, packaging, or mailing, ask your supplier for the actual caliper in mm, pt, or microns.
Many buyers also ask about 14pt to GSM or 16pt cardstock in GSM. There is no exact conversion, but as a rough reference, 14pt cardstock is often around 300–350 gsm, while 16pt cardstock is often around 350–400 gsm. The final value still depends on the paper grade, coating, density, and supplier.
For production, always confirm both the GSM and actual caliper before approving the material.
How to Calculate the Weight of One Sheet, a Ream, or a Box of Paper
You can also use GSM to estimate the weight of one sheet, a ream, or a box of paper. This is useful for shipping estimates, material comparison, and production planning.
Paper Sheet and Total Weight Formula
Use these formulas to estimate the weight of one sheet, a ream, or a full box of paper.
Calculate One Sheet
Sheet area should be measured in square meters. The result is the approximate weight of one sheet in grams.
Calculate a Ream or Box
Multiply the weight of one sheet by the total sheet quantity to estimate the weight of a ream, stack, carton, or box.
A4 Paper Weight Example
A4 paper measures 210 × 297 mm, which is close to 1/16 of a square meter.
For 80 gsm A4 paper:
80 gsm × 1/16 = about 5 grams per sheet
| Item | Approx. Weight |
|---|---|
| 1 sheet of 80 gsm A4 paper | 5 g |
| 100 sheets of 80 gsm A4 paper | 500 g |
| 500 sheets of 80 gsm A4 paper | 2.5 kg |
This is why a standard ream of 500 sheets of 80 gsm A4 paper weighs about 2.5 kg, before packaging.
U.S. Letter Paper Weight Example
U.S. letter paper measures 8.5 × 11 inches. Regular U.S. printer paper is often 20 lb bond, which is close to 75 gsm.
One sheet of 20 lb letter-size copy paper weighs about 4.5 grams.
| Item | Approx. Weight |
|---|---|
| 1 sheet of 20 lb letter-size paper | 4.5 g |
| 100 sheets of 20 lb letter-size paper | 450 g |
| 500 sheets of 20 lb letter-size paper | 5 lb |
A ream of 500 sheets of 20 lb letter-size copy paper weighs about 5 lb.
Finishing processes such as lamination, spot UV, foil stamping, and packaging materials may increase the final packed weight. If shipping cost is important, confirm the finished sample weight before production.
How Packaging Buyers Should Use GSM and LBS Conversion
For packaging buyers, GSM and LBS conversion is useful when comparing paper specifications from different suppliers, especially when one quote uses U.S. basis weight and another quote uses GSM. It helps you understand whether two materials are in a similar paper weight range.
However, paper weight conversion is only the first step. Packaging performance also depends on the paper grade, actual caliper, stiffness, coating, grain direction, structure, finishing, and sample testing.
To better understand material options such as kraft paper, SBS C1S, SBS C2S, textured paper, metallic paper, and holographic paper, browse our paper material support library.
| Packaging Item | Conversion Is Useful For | What You Must Still Confirm |
|---|---|---|
| Folding carton boxes | Comparing cover lb, paperboard GSM, and similar board weight ranges | Paperboard type, caliper, grain direction, scoring, folding result, and cracking risk |
| Hang tags | Comparing cardstock weight | Stiffness, hole strength, lamination, edge quality, and finishing performance |
| Paper bags | Comparing kraft paper GSM or supplier paper specs | Paper grade, handle attachment, bottom construction, surface strength, and real load testing |
| Corrugated boxes | Comparing liner paper or printed face paper GSM | Flute type, liner grade, corrugated structure, ECT/BCT strength, and shipping test results |
| Rigid box wrap paper | Checking wrap paper weight | Wrap paper GSM, print surface, lamination, wrapping performance, and greyboard thickness separately |
| Inserts and cards | Comparing cover stock | Stiffness, flatness, coating, print quality, and surface finish |
For paper bags, GSM conversion is only one part of material selection. Carrying strength also depends on the paper grade, handle design, bottom structure, and real load performance. For a deeper checklist, read our paper bag properties guide.
For custom packaging, use the calculator to compare paper weight first. Then confirm the actual material sample, folding result, printing effect, finishing performance, and packaging structure before bulk production.
Conversion Mistakes to Avoid
Paper weight conversion is useful, but one number is not enough to choose the right paper for printing or packaging. Check these points before confirming your material.
- 01
Assuming All 100 lb Paper Is the Same
MistakeTreating 100 lb text and 100 lb cover as the same paper.
FixConfirm the paper category first. 100 lb text is about 148 gsm, while 100 lb cover is about 271 gsm.
- 02
Treating GSM to mm as an Exact Conversion
MistakeUsing a GSM to mm chart as an exact paper thickness guide.
FixUse thickness charts only as rough references. Ask for the actual caliper in mm, pt, or microns.
- 03
Using Text Weight Values for Cover Stock
MistakeChoosing cards, hang tags, or inserts based on text weight values.
FixFor stiffer printed pieces, compare cover weight instead of text weight.
- 04
Choosing Packaging Paper by GSM Alone
MistakeAssuming two papers with the same GSM will perform the same.
FixCheck paper grade, stiffness, coating, grain direction, scoring, and final packaging structure.
- 05
Skipping Samples, Caliper, and Folding Tests
MistakeApproving material only because the GSM or LBS conversion looks right.
FixConfirm the sample, caliper, print result, finishing effect, and folding performance before production.
FAQ About GSM, LBS, Paper Weight, and Thickness
300 gsm is about 111 lb cover, 203 lb text, or 80 lb bond. For cards, hang tags, covers, and packaging inserts, it is usually closest to about 110 lb cover.
250 gsm is about 92 lb cover, 169 lb text, or 66 lb bond. For cards and inserts, the cover weight comparison is usually the most useful.
100 lb paper does not have one fixed GSM value. 100 lb text is about 148 gsm, while 100 lb cover is about 271 gsm.
80 lb paper depends on the paper category. 80 lb text is about 118–120 gsm, while 80 lb cover is about 217 gsm.
No. GSM measures grams per square meter, while LBS is U.S. basis weight. LBS conversion changes by paper category.
Not accurately with a fixed formula. GSM measures weight, while mm, pt, and caliper measure thickness.
Regular U.S. printer paper is usually 20 lb bond, which is about 75 gsm. Premium office papers may use 24 lb, 28 lb, or 32 lb bond.
There is no single best paper weight for all packaging. Use GSM or LBS as a starting point, then confirm the paper type, caliper, stiffness, structure, and physical sample.
Paper weight conversion is only the first step. GSM and LBS tell you the weight, but not the stiffness, thickness, folding result, or hand feel. For printing and packaging projects, always confirm the final material with a physical sample.
Need Help Choosing the Right Paper Weight for Packaging?
Not sure whether your packaging should use 250 gsm, 300 gsm, 350 gsm, kraft paper, paperboard, or another material?
Share your product size, packaging style, artwork, quantity, and material requirements with EPACK. Our team can help recommend a suitable paper weight, paperboard type, caliper, finishing option, and sample solution for your custom packaging project.
