Skip to main content
This page lists the files you can send, the limits, and how each type converts to fax.

​
Supported files

​
Limits

  • Total size: 10 MB at most for all files of one fax together.
  • Markdown: 100 KB at most per file.
  • Content: a fax needs a cover page, attached files, or both.
Other types, such as ZIP archives, Excel files, or design files, are refused with “Unsupported file type”. Save or export them as PDF first.

​
More than one file

You can attach several files. They are put together into one fax, in the order shown in the list, after the cover page if you added one. The pages of all files count toward the price, and the preview shows the whole fax. To control the order fully, combine the files into one PDF before you upload it.

​
How files convert

Every file is converted to the same fax format, TIFF files too:
  1. Word and Markdown files are turned into PDF. Images are placed on pages.
  2. All pages are converted to black and white at 204 × 196 dpi.
  3. The preview is made from that result, so it shows exactly what will be sent.
Rendering usually takes a few seconds. A long document takes longer.

​
Notes by type

A PDF keeps its layout and fonts, so the preview is closest to your original. If you made the document in another program, export it as PDF for the most predictable result.
Word files are converted with LibreOffice. Fonts that are not available are replaced, so line breaks and page breaks can move. If the layout matters, export the file as PDF from Word and upload the PDF. Check the preview either way.
Use a scan or photo with dark text on a light background, taken straight on. Color and gray areas are turned into dot patterns, and light colors can fade.
Good for a letter written as plain text, for example by an AI assistant.
  • Kept: headings, lists, tables, bold, italic, quotes, and code. A long file becomes several pages.
  • Not kept: images (only their alt text is printed). HTML in the file is printed as text. A link prints its address after its text.
  • Size: at most 100 KB.

​
Prepare a document for fax

  • Contrast: black text on a white background. Remove light watermarks, colored backgrounds, and gray or colored text.
  • Text size: small print loses the most detail. Make important numbers bold.
  • Layout: standard margins. Content close to the page edge can be cut off.
  • Check the preview at 100% zoom before you pay.
See Low-quality confirmations for why a fax looks rougher than the original.

Step-by-Step Guide

Each screen of the form

Cover Pages

Add a text page before your documents