Packtech

PP Woven Sack Fabric GSM & Bag Weight Calculator

Mesh times denier, over 228.6, is the fabric GSM. The rest of the sack follows from its size.

Fabric Mesh & tapes
tapes/inch

Warp tapes per inch across the fabric. A 10 x 10 fabric has 10 in each direction.

tapes/inch
den

Grams per 9,000 m of tape.

den
mm

Width of the flat tape after drawing, used for cover and thickness only.

g/cm³

Plain polypropylene is about 0.90 to 0.91. Tapes made with calcium carbonate filler are denser.

Sack Size & coating
cm

Half the circumference of the woven tube. For a gusseted sack, measure with the gussets pulled out.

cm

Length of tube cut for one sack, including hem and bottom-fold allowances.

g/m²

Mass of the extrusion coating per square metre. Enter 0 for an unlaminated sack.

Weight of One Sack

— g

Fabric and lamination for both faces of the cut tube

Fabric & Sack

Woven Fabric GSM
— g/m²
GSM with Lamination
— g/m²
Fabric Area per Sack
— m²
Sacks per Tonne of Material
— sacks
Warp Tapes Across the Tube
— tapes
Warp Cover
— %
Weft Cover
— %
Warp Tape Thickness Implied
— µm

The 228.6 comes from the units alone: mesh is counted per inch (25.4 mm) and denier is grams per 9,000 m, and 9,000 x 0.0254 = 228.6. The formula ignores crimp, so a woven fabric weighs slightly more than it gives; check against a weighed square cut from the fabric. Sack weight counts fabric and lamination over both faces of the cut tube and leaves out sewing thread, a liner, a valve patch and printing ink. Cover above 100% means the tapes overlap; well below it leaves gaps that fine powders can sift through, which lamination or a liner closes. Warp tapes across the tube are what the circular loom must be creeled with for this width and mesh; round to the loom's own count. Tape thickness assumes a flat tape of uniform section. **This is a decision-support estimate only.** Confirm fabric GSM, strength and sack dimensions against your buyer's specification and test method.

PP Woven Sack Fabric GSM & Bag Weight Calculator — free, with the formula and a worked example, at Textile School.