File extensions are a group of letters that are seen after a file name. The file extension is used to indicate the format of your file. Contrary to popular belief, there’s an easy way to change the file extensions of many files on your Mac computer, at once. For example, if you would like to change various .htm file extensions to .html, you can easily do so.

However, you must keep in mind that the method below will only change the file extensions, and not the actual file type. This method also won’t change the file name, either. The method is very easy to carry out and only requires a few moments of your time. In order to get started and batch change file extensions on your Mac, follow the simple instructions below.

Batch Change File Extensions in Mac

As you probably guessed, you’ll carry out this method through Finder. In order to get started and use Finder to batch change the file extensions on your Mac, follow the simple instructions below.

1. Launch Finder.

2. Using the menu bar on the top left of your display, click on Finder.

3. From the drop-down menu that appears, click on Preferences.

4. Click on the Advanced tab.

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5. There will be a checkbox option labeled Show all filename extensions. Please enable this option. A small blue check should appear in the checkbox, when the option is enabled.

6. There will also be a checkbox labeled Show warning before changing an extension. Please disable this option. The blue check should disappear from the checkbox, when the option is disabled.

7. Using Finder, navigate to the files or folder of files that you would like to change the file extension for.

8. Select all of the files, and then right-click, using your trackpad or mouse.

9. From the right-click menu that appears, click on Rename XX Items….

10. From the Rename Finder Items window, select Replace Text from the drop-down menu.

11. In the Find section, enter the initial file extension. In the Replace with section, enter the file extension you would like to batch rename all of your selected files to, and then click on Rename.

If you follow all of the above steps correctly, then you will successfully be able to change the file extensions of the files you select. None of the names of the files will be changed in this process. You can use this method to change .jpeg files to .PNG extensions, .docx to .doc, .txt to .php, or anything else of the like. It’s recommended to change the file extension to something that is compatible and accurately represents the file type, otherwise applications may have trouble opening your files.

As you can see this method is very easy to carry out, and only requires a few moments of your time. If this method didn’t work for you, it’s likely that you didn’t enable the Show All filename extensions, or that you didn’t disable the file extension change warning, as said in step #5 and step #6. It is absolutely necessary that you enable and disable the two options, respectively.

If you don’t disable the file extension change warning, then you will repeatedly see a dialog box asking you to confirm the file extension change for each individual file. This will take a lot of time, and will be very troublesome for you. The good news is, after you change the file extensions for your files, you can easily revert back to the initial settings you had saved on Finder.