Caliper is the thickness of a paper measured under specified conditions. Usually expressed in thousandths of an inch (mils). One point, or mil, equals 1/1000th of an inch.  ...

Gsm = grams per square meter, or the gram weight of a hypothetical square meter of a particular paper.In our opinion, this is the best comparative measure of a paper because ...

In the metric system, the density of all types of paper and paperboard is expressed in terms of grams per square meter (g/m²). This quantity is commonly called grammage.  ...