How to Change a File Extension (And What It Really Does)

A file extension is the suffix at the end of a filename (e.g. .txt, .md, .json) that indicates the file type to your operating system. Sometimes, files are created with incorrect or missing extensions.

Changing a filename extension is purely a labeling operation. For instance, renaming document.txt to document.md changes the file label so Markdown editors recognize it. However, renaming photo.jpg to photo.mp3 does NOT convert image data into audio binary data.

Use ToolNova's free File Extension Changer to drag and drop single or batch files, select a new target extension preset, and download the renamed files instantly in your browser.