FINDING THE RIGHT SIZE FOR YOU
Although there are other standard means of measuring paper and paper products in existence, you probably have heard mostly of two leading systems, the International and the North American sizes.
Of the two, the International Standard seems to more effectively bridge the confusing gap between the various sizes currently in circulation, as it has the cascading system that makes it easy to either enlarge or reduce a document in size.
Simply put, in the A Series (used for documents and publications), A4 is half of A3; A3 is half of A2; A2 is half of A1, and so on.
As for the C Series (used for envelops and folders), its ratios are directly analogous to the A series: one would use a C4 envelop for an A4 paper, a C5 envelop for A5 paper, a C6 envelop for A6 paper, and so on.
See below for the most used sizes used in printing - the A Series, B Series, and the C Series.
Photo sizes on the other hand most commonly uses the American nR series, where "n" is the length of the shorter edge, measured in inches. See above the common photo sizes used in printing with the corresponding measurements in mm.
Finally, for the perfect size pull-up banner, notice that (except for the Small size), all sizes are maximum two meters high - a nice height just a little above the viewer's head - for the best coverage of your displayed message.