A4 vs Letter Size: Key Differences and When Each Is Used
https://fair-wiki.win/index.php/A4_vs_Letter_Size:_Key_Differences_and_When_Each_Is_Used
A4 and Letter sizes are the two most common paper standards, with A4 used globally and Letter prevalent in North America. A4 is slightly taller and narrower, while Letter is wider and shorter. The key difference lies in their aspect ratios and dimensions—A4 follows a consistent √2 ratio, making it ideal for scaling documents, whereas Letter works best for US-centric forms, binders, and printers. Knowing which to use avoids formatting headaches when printing or sharing documents internationally.