When you receive an attachment via email or a floppy on a disk or any file that comes your way and you are not sure of how to use it, first check the suffix of the filename. The suffix consists of the last 3 or 4 digits:

  • syllabus_1.doc
  • index.html
  • cats.jpg

Follwing is a list of suffixes to check for if you receive a file and you are not sure what it is or how it is used. If you have suggestions for additional files to add to the list, please let us know.


FilePlatformDescription
AI Windows, Mac Adobe Illustrator image file
BMP Windows bit map image
DB Windows Paradox database
DOC Windows, Mac MS Word document
DOT Windows, Mac MS Word template
DVI Unix, PC-DOS low-level format
EPS Unix, Windows, Mac Encapsulated Postscript file
EXE Windows, Mac program (or "executable") file; this can also be a self-extracting zip file
FLA Windows, Mac Flash movie
GIF Unix, Windows, Mac An image format commonly used on the web. This format is limited to 256 colors. MS Word can also "read" this image file.
HTM, HTML Unix, Windows, Mac HyperText Markup Language file: This is a text file that is read by web browsers (such as Google Chrome, Mozilla Firefox, Apple Safari, or Microsoft Edge)
JPG, JPEG Unix, Windows, Mac An image format commonly used on the web. MS Word can also "read" this image file.
MDB Windows MS Access database
PDF Windows, Mac, Unix Adobe Acrobat file
PICT Mac image file
PNG Unix, Windows, Mac This is an image format used on the web but is not as common as GIF or JPG.
PPT Windows, Mac MS Powerpoint slide show
PSD Windows, Mac Adobe Photoshop document
PST Windows, Mac MS Outlook export file
RTF Windows, Mac, Unix Rich-text format: A file containing text plus some formatting; this file type is sometimes used to convert documents from one word processor to another.
TEX Unix, PC (DOS) Text file used for LaTeX documents
TXT Windows, Mac, Unix Text file (also sometimes referred to as an "ASCII" file)
VBS Windows Visual Basic Script: BE AWARE! Do not open an email with a .VBS attachment as that is a common way that viruses spread
WPD Windows WordPerfect document
XLS Windows, Mac MS Excel spreadsheet
ZIP Windows compressed file; requires WinZip or Pkzip to be opened

Additional filetypes for reference