Paper Weights Explained

Overview

Paper weight descriptions vary by region and grade. North American text and cover stocks often use basis weight in pounds (for example 80 lb text, 100 lb cover). Much of the world uses grams per square meter (GSM). Caliper or point thickness describes how thick the sheet is, which matters for folding, inserting, and postal calipers.

Basis weight is not a universal thickness: 80 lb text and 80 lb cover are different because the “basis” sheet size differs by grade category. That is why converting through GSM or caliper is safer than comparing pound labels alone.

Presses and binders have minimum and maximum stock ranges. A beautiful heavy cover that exceeds booklet-maker thickness or crease capability becomes a finishing failure even if the PDF is perfect. Weight also affects opacity, show-through, and ink/toner laydown.

When customers say “cardstock,” translate to measurable specs: GSM or basis weight, coated/uncoated, and caliper if finishing is tight. Dockzio’s paper weight converter helps move between common units so CSRs and estimators share one language.

Step-by-step

1. 1. Identify the grade family

   Determine whether the stock is text/book, cover/card, bond/writing, or specialty. Pound labels only make sense inside a grade family.

2. 2. Convert to a shared unit

   Translate customer language into GSM or a plant-standard basis. Use a paper weight converter rather than memory for odd cross-grade requests.

3. 3. Check caliper for finishing

   For multipage books, folded mailers, and insert packages, thickness stacks faster than people expect. Compare total book bulk to binder and stitcher limits — not only single-sheet weight.

4. 4. Match press capability

   Confirm the chosen stock is within the press’s supported range for simplex/duplex and for any specialty path (envelopes, banners, synthetic).

5. 5. Proof show-through and stiffness

   Lightweight text stocks may need opacity checks for heavy solids. Ultra-stiff covers may need score rules before folding. Sample when the job is brand-visible.

Common mistakes

• Equating lb text with lb cover. They are not the same thickness or stiffness. Always convert via GSM or mill caliper data.
• Ignoring duplex and grain. Weight alone does not capture grain direction, which affects fold cracking and binder feed.
• Specifying weight without finish. 100 lb gloss cover and 100 lb uncoated cover behave differently for ink holdout and postal scuff. Include finish in the spec.