Below are the paper dimensions used in graphic design. I remember when I was preparing for my first job (pre-internet), suddenly realising that I didn't know the basic paper measurements off the top of my head. After some hurried measuring with a big ruler, I was up to speed...
The ISO paper size is based on the concept that the height-to-width ratio of all pages is the square root of two (1.4142 : 1), as is demonstrated by our free downloadable cheat-sheet poster (covers A0 to A7):
Download the Free ISO 216 Page Sizes Cheat Sheet Poster (PDF)
If you'd like to download the above poster and spread the word at the same time, we'd be very grateful!
Most documents created in a graphic design environment conform to standard paper dimensions. It's handy to have these measurements to hand, so below are some of the commonest paper sizes used in the design and print industry, including the standard ISO A sizes as well as DL (compliment slip size) and standard business card sizes.