Letter vs A4 – what's the difference in size?
A4 is 210×297 mm; US Letter is 8.5×11 inches, or 215.9×279.4 mm. Compared with Letter, A4 is 5.9 mm narrower and 17.6 mm taller. Most of the world uses A4, while the United States, Canada and Mexico (plus a few other countries) mainly use Letter. You don’t need to worry about it to print pictures, though: the layout tool supports both. Pick one under Paper and the layout adapts.
Side by side
| A4 | Letter | |
|---|---|---|
| Size in mm | 210×297 | 215.9×279.4 |
| Size in inches | about 8.27×11.69 | 8.5×11 |
| Pixels at 300 DPI | 2480×3508 | 2550×3300 |
| Aspect ratio | about 1.414 | about 1.294 |
| Area | about 623.7 cm² | about 603.2 cm² |
A4 belongs to the ISO 216 A series. Its sides are in the ratio √2, so folding it in half gives the same shape: A3 folded is A4, and A4 folded is A5. Letter is a traditional North American size with no such relationship.
What happens if you print on the wrong one
- An A4 document on Letter paper: Letter is 17.6 mm shorter. At actual size, the bottom of the page is cut off; with “Fit to page”, everything shrinks to about 94%.
- A Letter document on A4 paper: Letter is 5.9 mm wider. At actual size, roughly 3 mm is lost on each side; with “Fit to page”, everything shrinks to about 97%.
For an ordinary letter or report, a little shrinking hardly matters. For anything that has to be a real size, such as an ID card copy or a receipt you need to measure, it does.
Which one should you use?
Check the paper in your printer’s tray or the label on the pack. In North America you’ll almost always find Letter (and Legal, 8.5×14 in); in the UK, Europe, Australia and most of Asia, A4. You’ll mainly meet the other size when you print a file someone made abroad, or send one to be printed there.
Switching in the layout tool
Each version of this site starts with its local paper size, but you can change it under Paper in the toolbar and choose portrait or landscape. Everything already on the page is laid out again on the new paper. ID cards and PDF pages keep their real size; only their positions change.
Exported PDFs are exactly the size of the chosen paper. When printing, choose the same paper in the print dialog and set the scale to Actual size.
Open the photo layout tool, choose your paper and start arranging.