How to Use This Tool
Use the entered basis-sheet dimensions instead of treating pounds per ream as one universal conversion. Convert paper GSM to pounds per 500-sheet basis ream with editable basis-sheet width and height, plus reverse-check values.
The decision this tool supports
The same GSM maps to different pound basis weights for bond, book and cover stocks because each grade uses a different basis sheet. This page keeps the decision bounded to basis weight and the supporting outputs shown beside it. GSM Basis Weight does not import an account, infer a market rate, or silently substitute an industry average.
Inputs and units
The GSM Basis Weight calculation uses Paper grammage, Basis sheet width, Basis sheet height, Sheets per basis ream. Keep all money values in one currency and all time, distance, mass, energy or volume entries in the unit printed beside the field. Mixing GSM Basis Weight scopes can produce a plausible number with the wrong meaning.
- Paper grammage is entered in g/m².
- Basis sheet width is entered in inches.
- Basis sheet height is entered in inches.
- Sheets per basis ream is entered in sheets.
Formula and worked check
Basis ream mass = GSM × basis-sheet area in m² × sheets per ream; pounds divide grams by 453.59237. 80 GSM on a 25 × 38 inch, 500-sheet basis ream converts to 54.05 lb; the reverse calculation returns 80.00 GSM. The GSM Basis Weight default is an executable known-answer case, not a benchmark or recommendation. Change one input and verify that the direction of basis weight still matches the stated relationship.
How to interpret the result
Enter the trade basis dimensions and ream definition from the paper specification; the round-trip output should reproduce the entered GSM. The additional GSM Basis Weight outputs expose the denominator, comparison, capacity or reverse value needed to audit the primary result instead of presenting one unexplained number.
Assumptions
- Basis dimensions refer to one untrimmed trade sheet.
- The entered ream sheet count matches the quoted basis weight.
- One inch equals 0.0254 m and one pound equals 453.59237 g.
Save the GSM Basis Weight input values and date with any material decision. A later GSM Basis Weight rerun is reproducible only when the same assumptions and units are available.
Limitations and safety boundary
Nominal merchant weights may be rounded and actual mill tolerances, moisture, caliper, bulk and grain direction are not converted. GSM Basis Weight is an estimate and cannot replace a contract, local code, licensed professional, calibrated measurement, lender statement or platform report where one governs the decision.
Source and privacy
The GSM Basis Weight definition or rule was checked against Library of Congress — Bond paper basis-weight specification on 2026-08-26. Recheck Library of Congress — Bond paper basis-weight specification when a specification or policy behind GSM Basis Weight can change. GSM Basis Weight arithmetic runs in this browser tab; ecech does not receive the values through a calculation API.
Sources & assumptions
Tool Spec v2 · verified 2026-08-26. Platform rules and fees can change; the editable inputs remain authoritative for your account.
Official references
- Library of Congress — Bond paper basis-weight specification (checked 2026-08-26)
Model assumptions
- Basis dimensions refer to one untrimmed trade sheet.
- The entered ream sheet count matches the quoted basis weight.
- One inch equals 0.0254 m and one pound equals 453.59237 g.
- Nominal merchant weights may be rounded and actual mill tolerances, moisture, caliper, bulk and grain direction are not converted.
