File Extension Mass Changer

File Extension Mass Changer is a straightforward application that enables you to rename the extensions of multiple files at the same time. It contains approachable options that can be tackled even by users less experienced with file management software.

Portable tool with a simple GUI

The entire program's packed in a single file that you can copy to the local or removable disk to carry it around and deploy it on any PC without previous installation. It doesn't change Windows registry settings, create files on the disk without your permission, or need any DLLs to run.
Regarding the interface, File Extension Mass Changer adopts a standard window with a plain appearance and neatly organized structure, where you can quickly dive into the configuration procedure.

Replace old extensions or add new ones

It's possible to indicate a directory whose containing files you want to take into account for processing, include or exclude subfolders, specify the file extension you're intending to edit, set the new one, as well as choose the action between replacing the old extension with the new one, or just appending the new one. An option is put at your disposal for undoing the last modification. Afterward, you can open the folder in Windows Explorer to inspect results.

Evaluation and conclusion

Tasks were carried out fast in our tests, during which the utility remained light on system resources consumption, thanks to the fact that it needed a low amount of CPU and RAM to work properly. No error messages were displayed and the app didn't freeze or crash.
On the other hand, it lacks some useful options, such as previewing the renamed files. Nevertheless, File Extension Mass Changer gets the job done and it's free for non-commercial use. No recent updates have been made, though.