In Windows 10, how do I show the file extension?

  1. Open Windows File Explorer.
File Explorer Icon on Task Bar in Windows 10
  1. Select the View tab from the Ribbon.
The View Tab in File Explorer in Windows 10
  1. Select the File name extensions tick box.
File Name Extensions check-box in File Explorer in Windows 10

Now you can see file extensions in the file name list.

Alternative solution: There is a setting called Hide extensions on known file types in File Explorer Options.

  1. In the search bar (located on the left-hand side of your taskbar), type File Explorer Options.
  1. Select the File Explorer Options in the search result list.
File Explorer Options on Search Bar in Windows 10
  1. Under the View tab, uncheck Hide extensions for known file types and click OK.
Hide Extensions for Known File Types in File Explorer Options on Windows 10

File Explorer Options can also be accessed directly from the File Explorer.

  • On the File menu, choose Change folder and search options.
Open File Explorer Options from Explorer Window in Windows 10

So what exactly do the file types serve? 

The main reason for using file types is that the operating system (Windows) and the programs can tell what file types they can handle; you cannot edit the audio file with a word processor.

If you have a file named Presentation.pptx, Windows knows it’s a Powerpoint document and will open it in Microsoft Powerpoint.

We often talk about file types when we mean file extensions. The problem is not bad because the file type is inferred from the file extensions.

A file extension is usually three or four digits long, but it may be longer.

Why should you show file extensions in Windows?

Setting Windows to display file extensions is useful for security. For example, the .exe is one of the extensions that Windows runs as a program when you double-click on the file. When you can’t see the extension, you can’t tell whether it is a safe document or a harmful program.

How displaying file extensions can benefit you?

You might have a file called “Presentation” that shows a PDF icon. But is it really a PDF-file? 

  • If the file extension is hidden, there is no quick way to see if it is a legitimate PDF or malware that uses the wrong icon as a cover.
File Name Extensions hidden in Windows 10
  • If Windows displays file extensions, you’ll quickly see whether it’s a secure document called “Presentation.pdf” or a malicious file called “Presentation.exe.” 
Show File Name Extensions in Windows 10