GSM stands for grams per square metre — the weight of one square metre of a given paper. It's the single most common spec you'll see on a paper data sheet, and for good reason: it's a quick, standardised way to compare stocks from different mills.
GSM isn't the same as thickness
Two papers at the same GSM can feel noticeably different in the hand. A dense, tightly calendered sheet packs more fibre into less volume, so it can weigh the same as a fluffier, bulkier sheet while feeling thinner. Thickness (often called caliper, measured in microns or points) and GSM are related but independently specified — when a project depends on a precise sheet thickness (fitting a machine feed, a die-cut tolerance, an envelope window), ask for caliper alongside GSM rather than assuming one implies the other.
Typical GSM ranges and what they're used for
- 35–55 GSM — newsprint and lightweight text papers
- 70–100 GSM — everyday office and offset printing paper
- 120–170 GSM — brochures, flyers, letterheads, better stationery
- 200–300 GSM — postcards, business cards, covers, light board
- 300 GSM+ — rigid boxes, presentation folders, premium packaging boards
Choosing the right GSM for your project
Start with how the piece will be handled. Something that passes through many hands repeatedly — a menu, a swing tag, a business card — needs enough weight to resist creasing and wear. Something folded (a brochure, a greeting card) needs to be heavy enough to hold its shape but light enough to fold cleanly without cracking at the spine. For packaging, GSM is usually secondary to the board's overall construction (single-ply, duplex, triplex), but it still sets the baseline for rigidity and perceived quality.
If you're unsure which GSM suits your application, our team can talk you through options based on your finishing process, printing method and how the final piece will be used — reach out and we'll help you narrow it down, with samples if you'd like to feel the difference yourself.