Q. How do I know A4 paper is GSM?

Calculating GSM involves multiplying the sample's weight in grams by 1000 then dividing that number by the sample's area in square centimeters. The GSM of paper and cloth may be calculated with the use of a Presto GSM calculation kit. The GSM cutter and digital GSM balance are included in this set. The first dimension is the item's length and breadth while the second is its mass and wall thickness. ISO A is a metric system used to describe the size of paper used internationally. With this method an A0 is one square meter in size. Another international standard ISO C specifies envelope sizes to accompany the multiple A paper sizes.