Key takeaways
- A4 is 210 × 297 mm and used almost everywhere; US Letter is 8.5 × 11 in (216 × 279 mm) in the US, Canada and a few other countries.
- Scanners that keep "real proportions" avoid stretching pages to the wrong size.
- Choose A4 or Letter when a document must print on standard paper.
- Printing across formats usually works with "Fit to page".
Ever printed a document and found the bottom lines cut off, or odd white margins? The culprit is usually the page size: A4 vs US Letter.
The two common sizes
| Size | Millimetres | Inches | Used in |
|---|---|---|---|
| A4 | 210 × 297 | 8.27 × 11.69 | Europe, Israel, Asia, Africa, Australia, most of the world |
| US Letter | 216 × 279 | 8.5 × 11 | USA, Canada, Mexico, Philippines |
| US Legal | 216 × 356 | 8.5 × 14 | North American legal documents |
A4 is slightly narrower and taller than Letter.
Page sizes when scanning
A good scanner app measures the page and keeps its real proportions — a receipt stays long and narrow, a Letter page stays Letter-shaped. In Scan to PDF:
- Auto (fit to page) keeps the real proportions of each page (at A4 width).
- A4 or US Letter places every page on standard paper — best when the document will be printed or submitted to an office.
Page sizes when converting images
In JPG to PDF, choose Same as image for on-screen viewing, or A4 / US Letter / Legal for printing. See convert JPG to PDF.
Printing across formats
Printing an A4 PDF on Letter paper (or the reverse) works if you select Fit to page or Shrink oversized pages in the print dialog. Choosing "Actual size" may cut off edges.
ID cards
ID cards have their own standard: 85.6 × 54 mm. Osd-Scan's ID card mode places them at real size on an A4 page. See scan an ID card front and back.
Knowing the difference saves wasted prints and rejected uploads.
Frequently asked questions
Which countries use US Letter?
Mainly the United States, Canada, Mexico, the Philippines and parts of Latin America. Most other countries use A4.
What size does Osd-Scan use?
Auto keeps the real proportions of each scanned page. You can choose A4 or US Letter instead to place every page on standard paper.
Will an A4 PDF print on Letter paper?
Yes, choose "Fit to page" or "Shrink to fit" in the print dialog. Margins may change slightly.
What is Legal size?
US Legal is 8.5 × 14 in (216 × 356 mm), used for some legal documents in North America.