Cover Weight to GSM Calculator
Convert cover-stock basis weight to GSM. Use it to compare paper specifications without treating GSM and U.S. basis-weight categories as interchangeable.
Enter your job values
Use the real values from your job. Optional fields can stay blank; zero should only be used when the value genuinely does not apply.
Your result will appear here
1 required value is still missing.
“80 lb” is incomplete without the paper category
U.S. basis weight uses 500 sheets of a category-specific basis size. Bond/writing, text/book, cover and index therefore produce different pound numbers for the same GSM. GSM is mass per square metre and does not change with the sheet size.
| Category | Common basis sheet | What the lb number refers to |
|---|---|---|
| Bond / writing | 17 × 22 in | 500 basis sheets |
| Text / book | 25 × 38 in | 500 basis sheets |
| Cover | 20 × 26 in | 500 basis sheets |
| Index | 25.5 × 30.5 in | 500 basis sheets |
What the result is useful for
Cover Weight to GSM Calculator helps separate grammage, U.S. basis weight, sheet mass and caliper so paper can be compared using the measurement that actually controls the buying, shipping or binding decision.
How the calculation works
GSM is derived from pounds using the fixed basis-sheet dimensions for this paper category.
What this calculator cannot know
Paper caliper, stiffness, coating and bulk are separate properties from GSM/basis weight. Manufacturer specifications and physical measurements control machine/binding suitability.