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Grammage guide

Grammage is the mass of one square metre of paper or board, expressed in grams per square metre (g/m², often written gsm). It is the most common way to specify how heavy a paper is. In North America basis weight is also given in pounds per ream, which depends on the sheet size used for that grade.

Grammage is not the same as thickness. Thickness (caliper) is measured in micrometres, and the ratio between the two – bulk – varies widely: a bulky board can be much thicker than a dense paper of the same grammage. A commonly used dividing line between paper and board is around 224–250 g/m², but there are many exceptions, such as lightweight boards and heavy papers.

The ranges in this database are typical commercial ranges, not standards. The chart below shows every grade on a logarithmic scale from 5 to 3,000 g/m².