Windows doesn't show file extensions by default, but you can change a single setting and make Windows 7, 8, or 10 always show you each file's full file extension.

Why You Should Show File Extensions

Each file has a file extension that tells Windows what type of file that is. File extensions are usually three or four digits long, but can be longer. For example, Word documents have the .doc or .docx file extension. If you have a file named Example.docx, Windows knows it's a Word document and will open it with Microsoft Word.

There are many different file extensions. For example, audio files may have a file extension like .mp3, .aac, .wma, .flac, .ogg, or many other possibilities depending on what type of audio file they are.

Setting Windows to show file extensions is helpful for security. For example, the .exe file extension is one of many file extensions that Windows runs as a program. If you can't see what a file's extension is, it's hard to tell whether it's a program or a safe document or media file at a glance.

For example, you may have a file named "document" that has the icon of your installed PDF reader. With file extensions hidden, there's no quick way to tell if this is a legitimate PDF document or is actually a malicious program using your PDF reader's icon as a disguise. If you had Windows set to show file extensions, you'd be able to see whether it's a safe document with the name "document.pdf" or a dangerous file with a name like "document.exe". You could look at the file's properties window for more information, but you don't need to do that if you've enabled file extensions.

How to Show File Extensions in Windows 8 and 10

This option is easily accessible in File Explorer on Windows 8 and 10.

Click the "View" tab on the ribbon. Activate the "File name extensions" box in the Show/hide section to toggle file extensions on or off. File Explorer will remember this setting until you disable it in the future.

How to Show File Extensions in Windows 7

This option is a little more hidden on Windows 7, where it's buried in the Folder Options window.

Click the "Organize" button on Windows Explorer's toolbar and select "Folder and search options" to open it.

Click the "View" tab at the top of the Folder Options window. Disable the "Hide extensions for known file types" checkbox under Advanced settings. Click "OK" to change your settings.

This options window is also accessible on Windows 8 and 10—just click the "Options" button on the View toolbar. But it's faster to quickly toggle file extensions on or off via the ribbon.

This window is also accessible via the Control Panel on any version of Windows. Head to Control Panel > Appearance and Personalization > Folder Options. On Windows 8 and 10, it's named "File Explorer Options" instead.

The above article may contain affiliate links, which help support How-To Geek.