A4 vs US Letter PDF Page Size: Which Should You Use?
Understand A4 and US Letter dimensions and what happens when PDF pages are resized.
A4 and Letter are different shapes
A4 measures 210 × 297 mm, while US Letter measures 8.5 × 11 inches. Their aspect ratios are close but not identical, so fitting one onto the other can create margins or require scaling.
Resizing changes the page canvas
A PDF page-size tool can place existing page content onto a new A4 or Letter canvas. Depending on the fit method, content may scale slightly or gain extra margins to preserve the original proportions.
Choose based on the destination
A4 is common across much of the world, while Letter is common in the United States and some related workflows. Printers, offices and submission systems may expect one size specifically.
Check important layouts after conversion
Forms, crop marks, signatures and precisely positioned content can be sensitive to scaling. Open the converted PDF and verify page edges and alignment before printing or submitting it.