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.
Tips and examples
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 packaging, quote both GSM and caliper (microns) because converters need stiffness, not just weight.