Discover File Extensions Easily

A file extension is the suffix at the end of a file name that indicates its type and format.
For example:

.docx → Microsoft Word document

.jpg → Image file

.mp4 → Video file

File extensions help your computer understand which software can open the file and how to process it.

Check the file extension and use the appropriate software listed on our site. We provide compatibility information for Windows, Mac, and Linux.
Tip: Always be careful with files from unknown sources — scan them with antivirus software before opening.

In most modern operating systems like Windows and macOS, file extensions are not case sensitive.
For example:

.PDF is treated the same as .pdf

However, some operating systems (like Linux) do distinguish between uppercase and lowercase. So it’s always safest to use the standard lowercase extension.

Try alternative software options listed on the file extension page. Some files may require specific software or codecs.