File Types Supported by Email-to-Fax Services

If you work with different types of files on daily basis, you need an online fax service that is capable of converting multiple documents to fax.

File compatibility is an important aspect to take into account when picking a provider, after all that’s a big part of what makes online faxing such a powerful tool!  The files you attach in your email fax message or that you send via your online fax account are all automatically converted into a fax image, a TIFF file actually, and then forwarded to the receiving fax machine.

Common Compatible Formats

These are the file types that are supported by the vast majority of online fax services out there.  Keep in mind that there are also websites that let you fax for free by following a simple form.  These websites offer a very limited amount of supported formats.  Some only allows you to upload PDFs, while other accept TXT and JPG files.  

File Extension



Adobe's Portable Document Format


Plain Text File


Microsoft Word


Joint Photography Experts Group


Windows Bitmap File


Compuserve Graphics Interchange Format


Hypertext Markup Language

Other File Formats

Besides the formats shown above, individual services may work with additional ones. Be sure to take a look at the FAQ section of the provider you are planning to use before creating an account, to check if your documents will be apt for fax conversion.

Your service may also support additional formats from programs such as:

  • Adobe Postscript
  • Adobe Photoshop
  • Amiga Interchange File Format (IFF)
  • Autocad
  • Word Perfect
  • Lotus 1-2-3
  • Lotus Word Pro
  • Microsoft PowerPoint
  • Microsoft Publisher
  • Microsoft Windows Write
  • Microsoft Works Word Processor
  • OpenDocument Drawing
  • OpenDocument Presentation
  • OpenDocument Spreadsheet
  • OpenDocument
  • Portable Network Graphics (PNG)
  • Quattro Pro
  • Visio Drawing

File Attachment Requirements

Keep this in mind to ensure your file is converted to fax:

  • Your attachment has a page size limit.  In general, you can't convert documents that have more than 200 pages.
  • The file must be named correctly to avoid conflicts during the conversion process. Avoid including ampersands and other special characters.
  • Check the file size limit.  Some services let you attach documents that combined weight less than 10- 20 MB while others let you work with large files like high resolution images.
  • Files that work with macros won't be converted.

What's The Service With Most Supported File Types?

Although RingCentral and eFax both offer plenty of supported file types.  The one that has the biggest list is MyFax.

This service is able to send all the file types we have mentioned in this article plus about a dozen more.

If you are working in a industry where you need to handle different types of files, or if you work with a very specific file type, you should check MyFax out.  You can also head over to our fax reviews to learn more about it.

There are additional factors that you should keep in mind though, like the size of files you are going to share and the amount of pages your documents are going to include.  If you work with large files, maybe you would be better with a service that is able to do so, and you convert your documents to a compatible file format manually.