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Grammage (g/m²)
Also known as: grammage, gsm, g/m2, basis weight, coat weight, film weight
Grammage is the weight of one square metre of a material in grams (g/m²), used for paper, films, laminates and adhesive coat weights.
Grammage is the weight of one square metre of material in grams (g/m² or gsm). In flexible packaging it is used for paper, complete laminates and adhesive or lacquer coat weights.
Grammage vs. thickness
Microns measure thickness; grammage measures weight. The link is density: grammage is roughly thickness in microns multiplied by density in g/cm³. BOPP (about 0.9 g/cm³) is noticeably lighter than PET (about 1.4 g/cm³) at the same thickness.
Where it is used
- Kraft paper is specified by grammage, often in the 50–120 g/m² range for pouches.
- Laminating adhesive and lacquer amounts are given as a few g/m².
- Total laminate weight helps estimate material usage, freight and reel length.
Because film is bought by the kilogram but used by the square metre, grammage tells you how many pouches a kilogram of material yields. When comparing quotes, check the layer materials and grammage, not just total thickness. Small differences in grammage add up quickly over large order quantities.
Frequently asked
How do I convert microns to g/m²?
Multiply the thickness in microns by the material's density in g/cm³. For example, 20 µm of a 0.92 g/cm³ PE is about 18.4 g/m².
What gsm is kraft paper in pouches?
Kraft paper used in laminated pouches is commonly somewhere around 50–120 g/m², chosen for look, feel and stiffness.
Related terms
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