BOPP bag calculation: laminated woven bag weight & cost
Calculate the weight of a BOPP laminated PP woven bag from fabric mesh and denier, extrusion coating GSM and BOPP film micron. Switch to a block bottom or metallised structure and see the laminated GSM and GPM the lamination line should hold.
Bag specification
A 1 Layer bag has no lamination. It is bare woven fabric, so there is no coating, no BOPP and no metallised film to enter. Pick a 2, 3 or 4 Layer construction above to add them.
Example rates only (₹ per kg). Real costing uses your own versioned price master in Nexora Sales & Costing.
Geometry, allowances and layer build-up follow the Nexora Sales & Costing engine: cut length from fold, hamming and patch overlap; coating and film spread over body width + 10 mm; film GSM = micron × 0.92. A liner is a separate article — use the liner calculator for it. Your plant's own constants, 29 constructions and the exact per-component result live in the app.
Costing is built from your own dated RM price master and process-wise resource rates — not from example rates. We will run your bag and your prices in a free demo.
Body, patch, valve, film, ink and thread grams with % share, plus the formula behind every value, are shown in Nexora Sales & Costing.
How a BOPP laminated bag is built up
A BOPP bag is a woven PP tube (typically 700–1000 denier at 10 × 10 to 12 × 12 mesh) laminated with a reverse-printed BOPP film through an extrusion coating sandwich. Three layers contribute weight: the woven fabric, the extruded coating that bonds the film, and the BOPP film itself.
BOPP film GSM = micron × 0.92 (e.g. 18 µm ≈ 16.6 GSM, 20 µm ≈ 18.4 GSM, 25 µm ≈ 23.0 GSM)
Laminated GSM = fabric GSM + coating GSM + BOPP film GSM
Bag weight = tube width × cut length ÷ 10,000 × laminated GSM + thread (+ patches for block bottom)
Typical BOPP bag specifications
- Rice, flour, sugar 5–25 kg: 800–900 denier, 10 × 10 mesh, 18–20 GSM coating, 18–20 µm BOPP, open mouth stitched or pinch bottom.
- Pet food, seeds, fertiliser: 900–1000 denier, 12 × 12 mesh, 20–25 µm BOPP, often block bottom with gusset.
- Metallised BOPP: same weight as clear BOPP of the same micron; the metallising layer is negligible in grams.
BOPP bag costing
BOPP film and extrusion coating resin are priced per kilogram and move with the polymer market, so a BOPP bag quote is only as good as the rate date behind it. The costing here uses example rates; in Nexora Sales & Costing every rate is versioned with an effective-from date, and the bag is costed component-wise (fabric, coating, film, ink, thread) with process-wise conversion cost and waste carried through lamination and printing.
FAQ
How do I convert BOPP micron to GSM?
Multiply micron by the film factor, 0.92 for standard BOPP (some films run 0.90). 18 micron ≈ 16.6 GSM, 20 micron ≈ 18.4 GSM, 25 micron ≈ 23.0 GSM. Nexora keeps this factor in the Constants Master so a plant can set its own.
What coating GSM is used for BOPP lamination?
Extrusion coating for BOPP lamination is typically 15–22 GSM of PP or LDPE-based resin. Enter your plant's figure in the coating field.
Does printing change the weight?
Reverse printing adds ink over the laminated area. The calculator uses the app default of 1.5 GSM.