How do I change a file extension on Android?

Last reviewed: October 21, 2026 · Markdown version

Rename the file and change the letters after the last dot. That edits the label, not the file. A photo saved as .jpeg and renamed to .jpg is the same picture under a name more apps expect; a .heic photo renamed to .jpg is still a HEIC photo, now carrying a misleading name. The rename itself is the easy part. Knowing which of those two cases you are in is what this page is for.

The rename steps Google documents

In Files by Google, open the app and "Tap a category or a storage device". In grid view, "Press and hold the file" and tap More; in list view, tap More next to the file. Then tap Rename, "Enter a new name", and tap OK (Rename a file, Files by Google Help, read 21 October 2026). That is the whole page. It does not mention the extension: whether the name box shows it, whether you may edit it, or whether the app warns you when you do. On all three it is silent (the Rename a file page above). Google's page on file details is no more help here: File info shows "details such as modified time and location of the file", and the page does not list the file type among them (View file information, Files by Google Help, read 21 October 2026).

On a Galaxy phone, Samsung's own My Files guides that we read cover moving, copying and making folders, and neither describes renaming a file at all (Manage files on your Galaxy phone or tablet, Samsung US, and Manage and organize files saved on your Samsung Galaxy device, Samsung CA, both read 21 October 2026). So on either phone, what the rename box shows is something to check on screen rather than look up.

What the change actually does

Microsoft's help states the principle more plainly than any Android page we found: you can change an extension, "but that won't convert the file to another format or change anything else about it except the file name" (Common file name extensions in Windows, Microsoft Support, read 21 October 2026). It is written for Windows, but the idea carries over. Android keeps its own lookup between the two: the platform reference describes MimeTypeMap as a "Two-way map that maps MIME-types to file extensions and vice versa" (MimeTypeMap, Android Developers, read 21 October 2026). Our reading of that: when an app goes by the extension, a new extension changes what the phone thinks the file is, and therefore which apps offer to open it, while the bytes inside stay exactly as they were.

When a rename is enough, and when it is not

Our rule of thumb, not a vendor statement:

Enough: two spellings of one format. Microsoft's list puts "jpg, jpeg" on a single row (the Microsoft page above), so switching between them is cosmetic. Also enough: putting back an extension a download lost, when you are sure what the file is.
Not enough: anything that needs a different format underneath. HEIC to JPG, DOCX to PDF and MKV to MP4 are conversions. Use an app that offers Save as or Export in the format you need, and keep the original until the copy opens properly.
If an app refuses the file afterwards, rename it back. Nothing was changed except the name, so nothing is lost.

How Adinand Auto File Sorter reads the extension

This is the one thing the app goes by. It sorts each file into a category from its extension alone, lower-cased, so IMG_01.JPG and img_02.jpg land in the same Images folder, and it never reads what is inside your files to sort them. That has two consequences worth knowing. A wrong extension sends a file to the wrong category, because the app takes the label at its word. And a file with no extension at all is never sorted; it stays where it is. The app does not rename anything itself: names are kept, apart from a (1) added when a different file with the same name is already waiting in the destination folder.