Have some files saved in the wrong file extension on your Mac? Don’t worry. You can easily change file extension in Finder on Mac. To do that, right click or Control-click on the file in Finder, then select Get Info from the contextual menu that pops up. You will get the file info window. Find the Name & Extension section, you can rename the file and/or change its extension there. Changing file extension for individual files on Mac is easy. What if there are a bunch files need to change the extensions? Let say we need to change file extensions for 100 files, do we need to repeat the above steps for 100 times? Fortunately, it’s easy to change your file extensions in Mac OS, you can follow these steps.
Batch change file extension for multiple files on Mac
Firstly find the files in Finder. Make sure you can see their current file extensions. If not, follow this tutorial to show file extensions on Mac.
Secondly you need to turn off the filename extension change alert on Mac, otherwise you will have to confirm the change for each individual file repeatedly. Click the Finder menu from the top menu bar, choose Preferences…, then switch to the Advanced tab in the Finder Preferences window. Disable the Show warning before changing an extension option from Finder Preferences.
Now let’s proceed to change file extensions for multiple files at the same time. Select all files you need to edit in Finder. Right-click (or Control Click) on them, you will get the contextual menu that pops up. Choose Rename xxx Items…. If you have selected 50 files, choose Rename 50 Items from the contextual menu, just as an example. You will get a new pop-up dialogue titled Rename Finder Items.
On this screen, choose Replace Text from the drop-down menu, type the current file extension, like .m4a, .html, .pdf, in the Find box, type the new file extension, like .mp3, .php, docx, in the Replace with box. Finally click the Rename button to complete.