Why the shapes differ
US Letter is 8.5 by 11 inches; A4 is about 8.27 by 11.7. Send an A4 page to a machine loaded with Letter and it is either shrunk to fit, which makes small print smaller, or printed at full size and trimmed at the foot. Neither is an error, and you will not be told which happened.
Lay out for both
- Keep margins generous. At least 15 mm, or about 0.6 in, on every side.
- Keep nothing important in the outer 10 mm. That band is where cropping and machine edges take their toll.
- Do not put page numbers at the very bottom. Put them inside the margin band instead.
- Avoid full-width tables that reach the paper edge. The last column is the one that goes missing.
What faxB2B does with your pages
Each page is rendered as an image at about 110 dpi and sent at its own proportions; we do not silently stretch A4 into Letter. Pages generated for you, such as a cover sheet, are letter sized. A page longer than 24 inches on a side is refused — that is usually a spreadsheet printed as one continuous page.
Mixing sizes in one fax
It is allowed: you can put an A4 scan and a Letter cover sheet in the same fax. The receiving machine then handles each page on its own, so the stack may come out slightly inconsistent. When the document has to look uniform, export the whole thing to one paper size before you upload it.
The mistakes that get a page cut off
- Open the preview and look at the foot of every page.
- Confirm nothing is cut at the right edge.
- If the recipient is in another region, assume their paper is the local size and check the margins again.
- When in doubt, ask which size they load — it costs one line on a cover sheet.