Grammage of paper and paperboard (weight per unit area), Test Method TAPPI/ANSI T 410 om-23
In the United States the customary or commercial term for expressing the “weight” per unit area (more properly “mass per unit area”) of paper has been “basis weight,” “ream weight,” or “substance.” These are defined as the mass in pounds of a ream of a given sheet size and number of sheets (usually 500 sheets, occasionally 480 sheets). In most other countries the mass per unit area is expressed in grams per square meter, g/m2. The French term for mass per unit area, “grammage,” is recommended by ISO Committee TC 6 on Paper for use in English as well as in French because of its convenience and clear relationship to g/m2.
Grammage of paper and paperboard (weight per unit area), Test Method TAPPI/ANSI T 410 om-23