A4 vs US Letter: which page size should your PDF use?
Updated 2026-09-30
| A4 | US Letter | |
|---|---|---|
| Width × height (mm) | 210 × 297 | 215.9 × 279.4 |
| Width × height (in) | 8.27 × 11.69 | 8.5 × 11 |
| Standard | ISO 216 | North American |
| Typically used in | Europe, the UK, Australia, India, Singapore and most of the world | The United States and Canada |
Which one should I pick?
- Pick the size your recipient uses. Government forms in the US and Canada are laid out for Letter; those in Europe, the UK and Australia for A4.
- If the portal only asks for a PDF upload and does not mention a page size, either works. The page size does not change the file limit.
- If you are printing, match your printer's paper. Printing A4 on Letter (or the reverse) scales or crops the page.
Converting images to a PDF at either size
The JPG/PNG to PDF tool places each image centred on an A4, Letter, Legal or A3 page, or sizes the page to the image. Images are only scaled down to fit inside the margins, never enlarged or stretched.
Changing the page size of a PDF you already have
Resize PDF pages puts each page on an A4, Letter, Legal, A3, A5 or custom-size sheet. Fit scales the whole page down or up to sit inside the sheet without stretching it, and leaves the spare space blank. Fill covers the sheet and clips what falls outside. Keep original size does not scale, and clips anything that does not fit.
Resizing places each page on the new sheet as a single graphic. Text stays text, but links, form fields and annotations on those pages are not carried over, and the tool tells you how many it found before you run it. If a page only has extra white border, Crop PDF pages trims it instead. Cropping hides the outside area rather than deleting it.
Frequently asked questions
- Can I change an existing PDF from A4 to Letter?
- Yes, with Resize PDF pages. Choose Letter and Fit. Links, form fields and annotations on the resized pages are not kept, and the tool counts them for you before it runs.
- Is A4 bigger than Letter?
- A4 is narrower and taller. It is 210 × 297 mm and Letter is 215.9 × 279.4 mm, so A4 is about 18 mm taller and 6 mm narrower.
- What paper size does Canada use?
- Canada uses Letter (8.5 × 11 in) for government forms and general printing.