Width × length × GSM = weight calculator
The most used formula in a packaging plant: area times GSM gives grams. Use it for a single bag panel, a tubular bag (two layers), a cut piece of laminated fabric, or a whole roll.
Piece / bag weight from GSM
Roll weight from GSM
For a circular-loom roll enter the tube width as 2 × flat width, or use the GSM to GPM tool with the tubular option.
No mesh or denier here. Weight comes from area × GSM. Mesh and denier decide the GSM — get it from the denier to GSM tool and enter it above.
The formula
Pick mm, cm or inch at the top of the tool and the sizes convert with it
Roll (kg) = width (m) × length (m) × GSM ÷ 1000
Example: a 50 × 90 cm tubular bag at 80 GSM. Area = 0.50 × 0.90 = 0.45 m² per layer, two layers = 0.90 m², weight = 0.90 × 80 = 72 g of fabric. Add fold allowance, coating, liner, ink and thread for the finished bag — the bag weight & costing calculator does all of that per structure.
FAQ
Should I use cut length or finished length?
Cut length. A stitched sack needs a top hem and bottom fold, so cut length is finished length plus 3–5 cm; a block bottom bag adds the bottom width.
How do I include lamination?
Use the laminated GSM: fabric GSM + coating GSM (+ BOPP film GSM). The BOPP bag calculator builds it from micron.