Paper and board GSM grades
GSM (grams per square metre) is the universal measure of paper and board weight. It runs from feather-light tissue around 20 gsm up to rigid solid board over 500 gsm, with every print and packaging grade in between. This reference maps GSM bands to grades and typical uses, plus a lookup that classifies any weight you enter.
How it works
GSM is the mass of a one-square-metre sheet, independent of the sheet’s actual size, which makes it a clean, comparable measure across formats. Heavier GSM generally means thicker and stiffer, though coating and bulk can shift the exact caliper. The lookup matches an entered value against the bands below and returns the grade and examples. For US suppliers, the table shows rough basis-weight equivalents — but note the US system uses different reference sizes for text, cover and index stock, so a single GSM has several pound equivalents.
GSM grade bands at a glance
| GSM range | Grade | Typical uses |
|---|---|---|
| 20–55 | Tissue / newsprint | Facial tissue, newspaper, wrapping tissue |
| 60–90 | Office / copy paper | Everyday printing, photocopying, forms |
| 90–120 | Quality text / letterhead | Premium letter paper, books, letterhead |
| 120–170 | Light card | Brochure inners, magazine pages |
| 170–250 | Medium card | Flyers, brochure covers, postcards |
| 250–350 | Heavy card / cardstock | Business cards, folding cartons, greetings cards |
| 350–500 | Solid board | Rigid boxes, book covers, premium packaging |
| 500+ | Corrugated / laminated board | Shipping cartons, display units |
Why the US pound system causes confusion
A single GSM value maps to different US pound figures depending on the reference size used for the paper grade. Eighty gsm text paper is approximately 54 lb text, because text stock uses a 25×38-inch reference ream. That same 80 gsm in cover stock would be around 22 lb cover, because cover stock references a 20×26-inch ream. This is why “80 lb cover” and “80 lb text” are dramatically different weights despite sharing the same number — always clarify which grade the pound figure refers to, or just specify in GSM.
Practical decision guide
Pick GSM by feel and function: 80 gsm for everyday printing, 100–120 gsm for letterhead with no show-through, 170–250 gsm for flyers and brochure pages, 300–400 gsm for business cards and folders, and corrugated board (single/double wall) for shipping cartons.
When ordering across borders, always specify in GSM — it is unambiguous, whereas “cardstock” or “heavyweight” mean different things to different printers. For structural packaging applications, quote both GSM and caliper (microns) because converters size for stiffness and stackability, not weight alone. Coated stocks (gloss, silk, matte) feel stiffer than uncoated at the same GSM, because the mineral coating adds rigidity — useful to know when comparing quotes that don’t specify coating type.