The sizes of printer paper are available in multiple forms, which mainly include international and regional standards. The series includes ISO A with sizes like A0, A1, A2, A3, A4, A5, and smaller, where each sheet is half of the previous one. Besides, there are B-series and C-series sheets used mainly for books, posters, and envelopes. Alternatively, North America has sizes like Letter (8.5 x 11 inches) and Legal (8.5 x 14 inches). Paper size is not only important if you print, but also affects design aspects such as layout spacing, scaling, etc. Because of this, you should use the right paper size for your job. That will save the trouble of re-editing the document and keep the print looking professional. It will also ensure that scaling is done correctly and that layout problems are prevented.