What Does GSM Mean in Printing?

GSM stands for grams per square metre, a measurement of paper weight based on how much a single square metre of that stock would weigh. Higher GSM values indicate thicker, more substantial paper, while lower values describe lighter, thinner sheets more suited to everyday documents.

Why is paper measured by weight rather than thickness?

Weight offers a consistent, standardised way to compare papers regardless of the material used to make them, since different paper types can be manufactured to the same thickness but end up with different densities and weights. Measuring grams per square metre gives printers and designers a reliable shorthand for describing how substantial a sheet will feel.

How does GSM affect the feel of a finished item?

A lower GSM sheet, such as those used for standard letters or internal documents, tends to feel light and can show some show-through of print from the reverse side. As GSM increases, paper becomes stiffer, more opaque and generally more resistant to bending, which is why heavier stocks are chosen for items meant to convey quality or durability.

GSM range	Typical feel	Common use
80-100gsm	Light, standard	Letters, internal documents
120-170gsm	Slightly firmer	Flyers, leaflets
250-300gsm	Card-like, sturdy	Covers, postcards
350gsm	Rigid, premium	Business cards

Does GSM change depending on the type of paper?

Yes. Coated and uncoated papers of the same GSM can feel quite different in the hand, because coating adds a smooth finishing layer that changes surface texture without necessarily changing overall weight by much. This is why comparing samples in person, rather than relying on GSM figures alone, is often the most reliable way to judge how a stock will feel.

How should GSM guide your choice of paper for a project?

The right weight depends entirely on the purpose of the finished item. A multi-page booklet benefits from a lighter internal weight to keep the finished item manageable, paired with a heavier cover for durability. A single-sheet flyer or postcard, by contrast, can use a heavier stock throughout since there is no folding or binding bulk to consider.

Are there other factors alongside GSM worth considering?

Finish, such as matte, gloss or uncoated, and the base material itself both interact with GSM to determine the final feel and appearance of a printed piece. Two stocks with an identical GSM figure can look and feel noticeably different once printed, so it helps to think about GSM as one part of a broader stock decision rather than the only consideration.

Why does understanding GSM help when briefing a print job?

Being able to specify a GSM range, rather than describing paper only as "thick" or "thin", gives far more precise instructions and helps avoid mismatched expectations between what is imagined and what is produced.

For more detail on choosing the right stock, see our paper GSM guide, or ask Minuteman Press Ipswich for paper samples before you decide.

Understanding GSM gives you the vocabulary to describe exactly the paper feel you want for your next printed project.