File Extension Batch Changer
Rename the extension across a batch of files in one pass — .jpeg to .jpg, .jfif to .jpg, and more.
What is Extension Changer?
A narrow, honest version of a batch renamer: it changes only the extension, showing which files are affected and in what way.
How it works
The batch is scanned for its extension mix, you pick which extension to match and what to replace it with, and the resulting names are previewed before the renamed copies are packed into a .zip. Contents are copied unchanged.
- Add your files. Drop files (or a whole folder) onto the drop zone. Browsers hand the contents straight to the page, so nothing is uploaded.
- Choose the options. Pick the format, compression, naming rule or split size. Any change re-computes the preview immediately.
- Download the result. Run the tool and grab the archive, the extracted files or the report. Multi-file results come back as a single .zip.
Examples
A 240 MB photo folder → a 52 MB .zip
JPEGs are already compressed, so the archive only saves 10–15% — but adding the folder structure and a manifest makes the upload verifiable.
A download cut off at 1.4 GB
The File Splitter cuts it into 500 MB chunks that fit the host's limit, and the File Joiner reassembles them, refusing any set with a missing part.
A release bundle with checksums
The Manifest Generator writes sha256sum-style lines next to the files, so the recipient can prove the download arrived intact.
Common mistakes
Expecting ZIP to shrink photos, video or audio
Those formats are already compressed; deflate typically saves single digits on them. ZIP is at its best on text, JSON, CSV, logs and source code.
Treating ZipCrypto as real encryption
Traditional ZIP encryption is legacy and breakable. It stops casual snooping only — for secrets, encrypt the contents with AES-256 first.
Renaming extensions to convert a file
Changing .png to .jpg does not change the bytes inside. Some programs will refuse the file, or display garbage. Use a real converter when the format must change.
Splitting without keeping the suffixes
The parts carry .001, .002 … suffixes on purpose: the joiner orders them by number and fails loudly when one is missing, instead of producing a corrupt file.
Frequently asked questions
Does this convert the file format?
No, and that distinction matters: renaming photo.png to photo.jpg does not make it a JPEG, and some programs will refuse to open it. Use the Image Format Converter when the format itself has to change.
When is this actually useful?
When the bytes are already correct and only the label is wrong — .jpeg files that a legacy tool insists be .jpg, .htm files served as .html, or a batch exported with the wrong suffix.
Can I match only one extension?
Yes. The matcher lists every extension found in the batch with its count, so you can rename only the .jpeg files and leave everything else untouched.