It is essential to select the right kind of paper or board, so you can achieve the best quality finish for your work. Papers and boards come in different weights and sizes. Paper is measured in gram per square meter(GSM), this refers to the weight per square meter. Anything over 200 GSM is classified as board. Normal paper for exercise books and photocopiers is about 80 GSM. Paper that is 160 GSM is twice as heavy (thicker). 500 GSM is thick card.