GSM is mass per unit area
GSM means grams per square meter. An 80 GSM sheet weighs 80 grams if its area is exactly one square meter.
Sheet weight
Sheet weight (g) = width(m) × height(m) × GSM
GSM is not thickness
Two materials with the same GSM can have different thickness because density, fiber, coating, porosity, and construction differ. Do not convert GSM to microns without material-specific density or manufacturer data.
Use the calculator
Move from the explanation into a live calculation using the related PackFlow tool.