GSM Grammage
Paper Weight & Grammage · 7 specs
Direct Answer
GSM (Grams per Square Meter / g/m², standardized under ISO 536) is the universal metric measure of paper areal density. Defining the exact physical weight in grams of a 1-square-meter (A0) sheet, it provides a linear, universal scale that eliminates the confusion of different paper grades and sheet sizes.
Source: ISO 536:2019 (Paper and board — Determination of grammage) / TAPPI T 410 · Last reviewed Aug 28, 2026
Specs
| Standard Metric Unit | g/m² (Grams per Square Meter — GSM) |
| Standard Copy Paper | 80 gsm (Standard European/Asian office paper — ~20 lb to 22 lb US Bond) |
| Premium Stationery / Letterhead | 100 to 120 gsm (Smooth premium corporate letterhead / resume paper) |
| Flyers & Magazine Pages | 130 to 170 gsm (Semi-gloss / silk coated marketing flyers and magazine interiors) |
| Greeting Cards & Booklet Covers | 200 to 250 gsm (Medium cardstock / folder covers) |
| Heavy Business Cards & Postcards | 300 to 350 gsm (Heavy rigid cardstock / luxury business cards) |
| Rigid Packaging Boxboard | 400+ gsm (Folding cartons, cosmetic boxes, presentation covers) |
Why GSM is Superior to Basis Weight
In North America, a 28 lb Bond paper is thicker than a 50 lb Text paper, and an 80 lb Text paper is much lighter than an 80 lb Cover paper, because each grade uses a completely different master sheet size. GSM is an absolute physical measurement: whether the material is tissue paper (20 gsm), copy paper (80 gsm), or luxury cardstock (350 gsm), the number directly reflects paper mass per unit area without ambiguity.
Postal Calculations
Because a single A4 sheet is exactly 1/16 m², dividing any paper's GSM by 16 gives the exact weight in grams of one A4 sheet (e.g. 80 gsm / 16 = 5.0 grams). Standard postal mail weight limits can thus be calculated instantly without weighing.