Paper Thickness & GSM for Packaging: How to Choose the Right Paper Weight

No — GSM is mass per area; thickness is measured in mm.

GSM measures grams per square meter, while thickness (caliper) is a physical dimension in mm. The two are linked by density, which varies by grade. Two papers with the same GSM can have different thicknesses and rigidity.

Not necessarily — strength depends on grade, density, and structure too.

Higher GSM means more mass per unit area, which often supports more rigidity, but it does not automatically mean stronger or better packaging. Board grade, density, and the finished structure all contribute. A bulky, low-density board of higher GSM may be less rigid than a denser board.

Only for a specific material — there is no universal conversion.

There is no universal GSM-to-mm conversion across all papers because the relationship depends on density, which varies by grade. A conversion is only valid for one specific material. Always quote both the GSM or thickness and the board grade together.

250–400 gsm is standard for SBS, CCNB, kraft, and metallic board.

Folding cartons are typically built in the 250–400 gsm range; the art-paper standard for a carton is roughly 250–350 gsm C1S. The right value depends on product weight, carton size, structure, print, and retail use.

Brown kraft 80–150 gsm and white kraft 90–150 gsm, with a 350–600 gsm base card.

Our kraft bags use brown kraft 80–150 gsm or white kraft 90–150 gsm. A reinforced base card of 350–600 gsm distributes weight. GSM is not a load capacity — handle, reinforcement, dimensions, and actual load all affect the correct specification.

By the grey board core thickness in mm — typically 1.0–3.0mm.

Rigid boxes are specified by the grey board core thickness (1.0–3.0mm; roughly 1200–1800 gsm), not by the surface paper GSM. The wrap paper (art paper 128–300 gsm) carries the print, while the core provides structure and rigidity.

Yes, but the surface, coating, and grade matter more than GSM alone.

Print quality depends mainly on the paper surface, coating, and material grade. A coated board prints brighter and holds fine detail; a kraft or uncoated stock gives a matte eco look at the same GSM. Choose the board for the print result, then confirm GSM / thickness for the structure.

Match the specification to the packaging type — GSM for cartons and bags, thickness for rigid, construction for corrugated.

Choose the primary specification that fits the packaging type: GSM plus board grade for folding cartons and paper bags, grey board thickness for rigid boxes, and board construction (flute + ECT) for corrugated. Then weigh product weight, dimensions, structure, print, and cost. When unsure, give the manufacturer your product and dimensions and let them recommend a board.