Paper Sizes A Series In the print industry, there are a range of paper and card stock sizes that are available. Some you will have already come across such as A4 paper and DL envelopes. The A series paper sizes are defined in ISO 216 (International Organisation for Standardization www.iso.org ). A0 is the largest and has an area of one square metre, A1 is half the size of A0, A2 is half the size of A1 and so on. Paper also comes in the B series and C series, but the A series is the most common in Australia. http://www.kalamazoo.com.au/paper-sizes/ DL Envelope Sizes Paper Weight When we talk about paper weight, we are referring to the thickness of the paper or card. ISO 536 outlines the standards for paper weights. Paper weights are measured as grams per square metre g/m2 or gsm. Because the A0 size is defined as being 1 square metre, the weight of this defines the other sizes of the same paper type. If the paper is 80gsm, which is the standard ...