gramaje

Gramaje, or grammage, is a measure of the mass per unit area of a material, typically expressed in grams per square meter (g/m^2). It is used to characterize sheets such as paper, cardboard, textiles, and films, indicating the weight of a given area independent of thickness. Grammage helps compare materials of similar size regardless of their actual thickness or density.

Measurement and standards are based on determining the mass of a precisely cut area and dividing by that area. In practice, samples are conditioned in a standard atmosphere, then weighed to constant mass with a precision balance. For paper and board, standard methods include ISO 536 (and similar TAPPI procedures in other regions). The result is reported as a grammage value in g/m^2.

Common ranges illustrate its use across materials. Paper and cardboard span roughly from 60 to 400 g/m^2, with writing papers around 70–100 g/m^2, office papers about 80 g/m^2, magazines near 100–150 g/m^2, and cover stock or packaging papers higher still. Textiles exhibit a wide variation, from about 100–180 g/m^2 for lighter fabrics to 300–600 g/m^2 or more for heavy textiles such as denim or upholstery.

Gramaje affects properties such as stiffness, opacity, durability, and production cost, and it is a primary criterion in selecting materials for printing, packaging, and textiles. It is related to, but not identical with, thickness, since density also influences the overall feel and performance of the material.