GSM

Grams per square meter: the weight of a paper, and a rough guide to how thick it feels.

Paper weight is measured in grams per square meter. Novel pages are often around 80 to 100gsm, picture book pages around 150gsm, and covers 250gsm and up.

Heavier paper usually feels sturdier and shows less through the page, but the finish and the paper itself matter too, so two papers of the same weight can feel different.