THE METHOD
Area × grammage.
Then count the sheets.
Papermass uses one entered rectangular sheet size and one entered grammage. All sheets in the calculation are assumed to be that same stock and size.
What gsm means here
Grammage is mass per unit area, expressed here in grams per square metre (g/m², commonly called gsm). TAPPI’s public T 410 description explains this unit and distinguishes it from US basis-weight conventions, which depend on a specified sheet size and ream count. This calculator does not guess a gsm value from “text”, “cover”, “bond” or a pound label.
ISO’s public record for ISO 536:2019 identifies a paper/board grammage test method. Papermass does not perform that laboratory method, determine the actual grammage, or certify compliance. Only public descriptions/records were consulted; no paid standard text is reproduced.
The four steps
- Convert the entered width and height to metres.
- Multiply width × height to obtain one sheet’s area in m².
- Multiply area × entered gsm to obtain grams per sheet, then multiply by the physical sheet count.
- If a separate additional batch mass is supplied, add it once. Otherwise the combined mass is unavailable.
One inch is exactly 0.0254 m; one millimetre is 0.001 m and one centimetre is 0.01 m. The arithmetic retains the entered decimal values and canonical physical dimensions. Unit changes preserve those dimensions internally. Editing a converted display value deliberately establishes a new entered dimension.
Worked example: 210 × 297 mm, 80 gsm
| Sheet area | 0.210 × 0.297 = 0.06237 m² |
|---|---|
| Nominal mass per sheet | 0.06237 × 80 = 4.9896 g |
| 500 physical sheets | 4.9896 × 500 = 2494.8 g = 2.4948 kg |
| With a known 100 g extra batch mass | 2494.8 + 100 = 2594.8 g = 2.5948 kg |
The entered rectangle is used exactly. It is not replaced by an idealised 1/16 m² area or a rounded 5 g sheet. Rounding each sheet to 5 g before multiplying would increase this example’s paper result by 5.2 g.
Worked example: small cardstock sheets
A 100 × 100 mm rectangle has area 0.01 m². At 300 gsm that is 3 g per sheet. For 100 physical sheets the nominal paper mass is 300 g. Adding one separately entered 50 g batch extra gives 350 g combined.
Zero and unknown are different
Zero sheets means zero paper mass. If a known 100 g additional mass is supplied with zero sheets, the combined result is 100 g. A known extra mass of 0 means the combined total equals the paper-only mass. A blank extra field means unknown: paper-only mass remains available, but the combined total does not become zero or pretend packaging is absent.
Physical sheets, not printed pages
A physical sheet can carry printing on either side. This tool does not turn a page count into a sheet count, inspect a PDF, allow for booklet signatures, nest cuts or choose a paper size. Enter the number of actual pieces of the stated rectangle.
Nominal mass and the export
Manufacturing variation, moisture, coatings, ink, glue, envelopes and binders can affect measured mass. No tolerance or correction for those items is assumed here. Grammage alone does not provide paper caliper, bulk density, stiffness or strength. The result is not a parcel billable weight, postage quote or carrier acceptance test.
Text and CSV exports retain exact canonical metre dimensions and the nominal decimal mass arithmetic. The chosen display units are included, with converted visual dimensions marked as rounded when necessary. Unknown additional and combined mass remain explicitly unavailable in the text and empty-valued with status labels in CSV.
Software bounds are 0.000000001–100 m per sheet dimension, 0.000001–1,000,000 gsm, 0–1,000,000,000,000 sheets, and 0–1,000,000,000,000,000 g additional mass. They are input limits, not claims about useful paper stocks. Entered number text is limited to 100 characters and decimal exponents to ±30.