How To: Change the extension of multiple files at once (batch)

Windows sometimes has problems with file extensions and will name files with the wrong one. This holds especially true for recovery applications that might recover your files but with the wrong extensions. Renaming the extensions for all those files one by one can be extremely time-consuming. However, you can change them easily all at once by using the command prompt. Furthermore, you can use an easy function in Windows Explorer to put the same name in all of the files in a numerical sequence.

1. Changing extensions


First of all, you will need to put all of your files in the same folder. Then hold shift and right click on a blank spot in that folder. Choose the “open a command window here” option from the context menu. Now you will need to use the “Ren” (rename) command.

Say you want to rename your JPG files to PNG.  You will use this command: Ren *.jpg *.png
This will turn all of the JPG file to PNG automatically. The asterisk is used to indicate that the name does not matter.

2. Renaming a batch of files


Say that you have a huge number of pictures from your trip to London. The picture files will usually be randomly named with numbers and other such characters. If you want to rename all of them “Trip to London” you can do it with Windows Explorer. Simply highlight all of the files and rename one of them, preferably the first. All the files will then be named “Trip to London” with their numerical order in a parenthesis like “Trip to London(1)”.