How to Spec Kraft Paper GSM for Shopping Bags and Mailers

Quick answer

Specify kraft GSM from the carry or ship case outward: fill weight, handle type, mailer contents, print coverage, and humidity exposure—not from a generic “120 gsm kraft” habit. The same GSM performs differently across virgin, recycled, and extensible grades.

Separate bag and mailer jobs

Retail carrier bags need handle pull and bottom strength. Mailers need puncture/tear resistance and often print on one face. Do not copy a shopping-bag GSM onto a mailer RFQ without retesting.

Lock grade with GSM

State virgin/recycled/extensible type, GSM tolerance, and any burst/tensile targets. Ask for retained sample sheets from the production lot.

Account for converting

Twisted handles, patches, gussets, and adhesive seams change the required paper. Heavy ink or soft-touch coatings can also reduce usable strength at stress points.

Validate with load and transit tests

Approve production-process samples with carry tests for bags or drop/abrasion checks for mailers. Freeze the approved grade before peak-season volume.

RFQ

Bag/mailer style; fill weight; handle or closure

Kraft grade; GSM; strength targets

Print/finish; moisture route; sample tests

Monthly volume; Incoterms; substitution ban

Related PackTrades Knowledge

What Is Sack Kraft vs Extensible Kraft for Packaging?, Kraft Paper Supplier Guide for Packaging Buyers, Twist-Handle Paper Bag Load Spec Checklist for Retail, How to Spec Paper Bag GSM and Bottom Construction.