Glossary
gsm (grams per square metre)
Definition
The weight of paper or board expressed as grams per square metre. Higher gsm generally means a thicker, stiffer, more durable material.
Also known as: Grammage, g/m2, Paper weight
gsm, short for grams per square metre, is the standard way of specifying how heavy a paper or board is. It states the mass of a one-metre-square sheet, so a 90gsm paper weighs 90 grams per square metre and a 300gsm board weighs 300. It is a weight measure, not strictly a thickness one, though the two usually track together for a given material.
For packaging buyers, gsm is a quick shorthand for feel and durability. Lightweight wrapping and void-fill papers sit lower on the scale, everyday printer and mailer papers are in the middle, and stiff card and folding boxboard climb higher. Comparing gsm only makes sense within the same material type, because different pulps and coatings vary in bulk.
gsm is different from micron, which measures thickness and is used for plastic films such as pallet wrap and mailing bags. When comparing papers, gsm is the figure to check; when comparing films, micron is the one that matters.
What to check
- Compare gsm only between the same type of paper or board.
- Match gsm to the task: lower for void fill, higher for rigid packaging.
- Remember gsm is weight, not thickness, so bulk can vary by material.
- For plastic films, check micron instead of gsm.
- Ask for a sample to confirm the feel before committing to a spec.
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gsm (grams per square metre) — FAQs
Does higher gsm always mean stronger?
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