Change File Extension Writing of many Files

I have a collection of countless files with file extensions that are written quite confused. For example, some files are ending with ".MP3", others with ".mp3", some even with ".Mp3". Now, I want that all extensions of all files should be written in an equal style (either all uppercase or all lowercase). Rewriting and renaming each file individually is too much work for me. What can I do?

Solution: With the FileRenamer you can rewrite and modify the file extension writing of multiple files simultaneously. The tool is available for the operating systems Windows, macOS and Linux.

1. We can just drag and drop the files we want to change from arbitrary folders onto the program. It is also possible to add entire folders this way.
2. Next, we can adjust what should be changed: For this, we are activating the option "Writing" in the section "Changes > Extension" on the right of the main window next to the file list.
3. Here, we can specify how the writing of the extension should be changed: only the first character uppercase and the others lowercase (Abc), all letters uppercase (ABC), all letters lowercase (abc) or random (aBc).
4. In the file list, the column "Preview" is showing the future name of the files. If you are satisfied with this, you can click on the button "Apply Changes" in order to rename all files in the list accordingly.

By the way, the application File Renamer can not only rename the writing of file extensions and file names. With the other options from the section "Changes", you can modify filenames and fileextensions also in various other ways. In addition, the program can additionally be used to edit the file dates and file attributes. You can find the corresponding settings directly under the settings for the name and the extension in the area "Changes > Attributes".