GSM means grams per square metre and describes a sheet’s basis weight. A square metre of 70 GSM paper weighs 70 grams; the same area of 80 GSM paper weighs 80 grams. It does not directly state thickness, because fibre composition, refining and calendering also affect caliper.
Handling and show-through
An 80 GSM office sheet generally feels firmer and is often more opaque than a comparable 70 GSM sheet. That extra substance can improve two-sided readability and feeding on equipment that prefers a stiffer sheet. A well-made 70 GSM grade can still run cleanly and may reduce the weight of large mailings.
Ten grams sounds minor, but a ream or a high-page-count document multiplies the difference. Procurement teams should compare total packed weight, printer settings and transport requirements rather than treating GSM as a quality score.
Which weight to specify
Choose 70 GSM for high-volume internal documents, manuals and transactional work where efficient material use matters. Choose 80 GSM when handling, opacity and a more substantial feel are priorities. Test the exact grade, because two papers at the same GSM can behave differently due to moisture, stiffness and surface treatment.
