Batch File Renamer
Apply a find/replace or numbered pattern across many files at once, with a live preview.
What is Batch Renamer?
A rule-based renamer for batches of files: strip a camera prefix from 400 photos, add an issue number to a set of assets, or convert a folder of spaces to kebab-case.
How it works
Rules are applied in a fixed order — find & replace, then prefix and suffix, then numbering, then letter case — to each name while keeping the extension untouched. The preview shows every change before anything is written, and collisions are resolved by appending -2, -3 when you leave the duplicate guard on.
- 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
Why can't it rename my files in place?
Browsers cannot write to a filesystem path you picked, by design. The renamed copies are delivered as a .zip with the same contents, ready to unzip over the originals.
How does numbering work?
The pattern uses {n} for the padded counter and {name} for the current filename, so `{name}-{n}` turns report.txt into report-01.txt with a padding of 2. Start value and padding are both configurable.
What happens if two files would get the same name?
With the duplicate guard on, the second one gets -2 before the extension. Turn it off and the clash is flagged so you can adjust the rules instead.
Are the files re-encoded?
Never. Names change, bytes do not — the archive holds byte-identical copies of your originals.