What Types of Files Can I Attach to a Gmail-Based Fax?

gmail fax file types

Faxing online has become the most effective way to fax without a fax machine. Long gone are the days when we had to rely on a fax machine or a physical faxing service at a nearby office store. Now you can fax directly from your computer and even your smartphone, just by attaching a file to a Gmail message.

Whenever you send fax​es via Gmail, this fax is converted into a format that is readable by fax machines, usually a TIFF file, which then is interpreted and printed accordingly on the destination’s fax machine. But what file formats or file types can be faxed online? In this article we will explore what are the most common formats accepted by online fax services as well as what is the best service to take care of more obscure formats.

What Happens When You Fax a File Over Internet?

Let’s begin by explaining what takes place when you send a fax online. Once you send a fax by email, it goes through a quick process that makes it readable by all legacy fax machines out there.

  • 1
    ​Your email fax is sent to your service’s powerful fax servers.
  • 2
    ​Then the file is converted into a format compatible with fax machines.
  • 3
    ​This file is transmitted from the servers to the fax machine, using FoIP technology (Fax Over IP)
  • 4
    ​Once it has been successfully sent, the service sends a confirmation message to your email.

As you can notice, this is a hands-free process, once you’ve finished setting up your Gmail fax. It is also very fast, the steps you’ve read above are completed in just a few seconds. If there’s an error during the transmission, your service will re-try sending it until it is completed.

File compatibility is very important because it saves us a lot of time. If your service is not compatible with a certain file format, you need to print it, scan it, and then send it. That’s a lot of unnecessary steps that not only waste your time, but your printing resources as well!

Common Files You Can Fax Online

These are the file formats that are commonly accepted by leading fax services. You can fax them without problems, even from free fax websites. Let’s take a look at them:


pdf file

This is the most common file type you can fax, and is also the file format in which you receive all your faxes via email.

The PDF is a digital document file type that is able to show text and images, and if read electronically can also show hyperlinks. The advantages of using PDF are many, but the most important is that you can read them on any computer.

PDFs are easily converted to fax, keeping a high readability level. Here’s a tutorial on how to fax a PDF.


Excel xls file

This is the file format used to save Microsoft Excel documents. You don’t need to convert your Excel file into a PDF, simply attach it to the email message and the service will read it and put your spreadsheet into a readable document.

If you are working with a document that has multiple tabs, each tab will be a new page, or pages depending on how long is the content on the page. This is another one of the most common formats accepted by fax services.


These are plain text files. Although this is a format that is easily readable and converted into fax form, it is used only in certain occasions due its inability to include photos, graphics or formatting.


These are editable text files that can also contain images. They are produced by programs such as Microsoft Word, or Pages. These are file types that are very common in today’s offices and because of that can b easily faxed online.

Images: BMP, JPG, PNG, GIF

These days you can find information and documents as scanned images, which are usually saved on your computer as JPG,BMP or PNG files, just to name a few. Maybe it’s a screenshot, maybe a photo of a physical document. It doesn’t matter, you can fax it within seconds.

Keep in mind that the image will be received as a black and white image, so if there are many images in the document, you might want to adjust the level of contrast before sending it.

Presentation: PPT, SHW, ODP

Presentation files made with Powerpoint or Corel Presentations can also be sent as fax. In this case, each page of the presentation will be a new fax page.

Faxing Obscure File Types

Besides these common file types, there are dozens of others that some industries might use. We are talking about file types such as:

  • ​Amiga Interchange File Format (IFF)
  • ​CAD Drawing Exchange Format (DXF)
  • ​Visio Drawings (VSD)
  • ​Microsoft Publisher (PUB)
  • ​PC Paintbrush Graphics (PCX)
  • ​Tagged Image File Format (TIFF)
  • ​Adobe Photoshop (PSD)

These are just to name a few. We can’t include a huge list of compatible file types, because they vary according to the supplier. It is a good idea to check out our reviews or search on Google for “(fax service) compatible file types”.

If you are looking for maximum compatibility, then you should try MyFax. From our testing this is the service that can work with the most number of file types. It works with dozens of rare file formats for word processors, generic text, DOS word processors, Mac word processors, spreadsheet formats, and database formats.

If on the other hand, you are working with common file types, and not-so-rare ones, any service will do. Services such as eFax or RingCentral may not be compatible with some of the file formats compatible with MyFax, but are still able to convert various digital files to fax.