What Is 3300 in the Poly Bag Formula?

If you have used the quick poly bag cost formula, you have divided by 3,300,000 and probably wondered where that number comes from. It is not arbitrary. The 3300 factor is a shortcut constant that bundles two fixed conversions together so you can price a bag from just its length, width, and gauge. Here is what it is, where it comes from, and the one material it is valid for.

The quick formula

Cost = (Length" × Width" × Gauge × Qty × $/kg) ÷ 3,300,000

Compared with the full formula (which spells out thickness in inches and density explicitly), this version lets you plug thickness straight in as gauge and skip the density lookup. The price you pay for that convenience is that the constant hard-codes a specific density.