At a glance: A4 is 210 × 297 mm (about 8.27 × 11.69 inches). US Letter is 8.5 × 11 inches (215.9 × 279.4 mm). Letter is 5.9 mm wider; A4 is 17.6 mm taller.
A4 and Letter dimensions side by side
| Sheet | Width × height in mm | Width × height in inches |
|---|---|---|
| A4 | 210 × 297 | 8.27 × 11.69, rounded |
| US Letter | 215.9 × 279.4 | 8.5 × 11 |
The dimensions describe sheets in portrait orientation. Rotating both sheets gives landscape sizes of 297 × 210 mm and 279.4 × 215.9 mm, respectively. Neither sheet completely covers the other at the same scale: their proportions differ.
Why this matters for a PDF
An A4 document may be too tall for a Letter sheet even though the Letter sheet is wider. At Actual Size / 100%, content near the top or bottom of the A4 page can clip. Some documents leave enough blank space that the text still prints; a border or an exact-size template needs a test. Printer margins reduce the usable area on either sheet.
If you need the entire A4 page inside Letter, the theoretical proportional fit without printer margins is about 94.07%. With 5 mm reserved on each Letter edge, it is about 90.71%. The A4-to-Letter scaling guide shows the formulas and the reverse Letter-to-A4 conversion. Our scale calculator accepts your margin allowance.
Choose the right paper before printing
- Check the PDF’s page size in document properties or your print dialog.
- Load the matching sheet if the design must keep its measured dimensions.
- For a reading copy on the other paper size, preview a proportional fit and check for tiny text.
- For a pattern or form with measurements, verify a marked reference length on one test print.
When printing a border to the edge, allow for the printer’s printable margins; selecting A4 or Letter alone does not enable borderless printing.
Is A4 the same as 8.5 × 11?
No. 8.5 × 11 inches names US Letter. A4 is approximately 8.27 × 11.69 inches. If a website offers both PDF versions, select the one that matches your loaded paper rather than asking the printer to resize a measured template.
Paper dimensions: Adobe paper-size reference. US Letter and Half Letter dimensions use 8.5 × 11 and 5.5 × 8.5 inches respectively; millimeters use 25.4 mm per inch. The scale and two-up examples are arithmetic, not printer tests.
PDF print settings: Adobe Acrobat page-sizing guide.