Batch Filename Renamer
Preview deterministic filename changes for locally selected files and export the mapping as CSV. Browsers cannot rename files on disk, so the tool makes no claim that the original files are changed.
Browser-localFreeNo upload required
What this tool is for
Preview deterministic filename changes for locally selected files and export the mapping as CSV. Browsers cannot rename files on disk, so the tool makes no claim that the original files are changed.
How to use
- Select files; only their names are read.
- Choose prefix, suffix, find/replace, case, and numbering rules.
- Resolve duplicate outputs, then export the mapping for use in a trusted local rename workflow.
Example
Rename `IMG_1001.JPG` and `IMG_1002.JPG` to `trip-001.jpg` and `trip-002.jpg` while preserving each extension.
FAQ
Are my files modified?
No. The page reads filenames and creates a mapping only.
Why are duplicate outputs blocked?
Two files cannot safely occupy the same path after a rename.
Reproducible examples
Known inputs and expected results
Run these examples in the workspace above and compare the result with the documented output.
Literal replacement and sequence
- Input
- IMG_1001.JPG; IMG_1002.JPG
- Options
- Find IMG_, replace with trip-, and add numbering from 1 padded to 3.
- Action
- Preview the mapping.
- Expected output
- trip-1001-001.JPG and trip-1002-002.JPG.
- Explanation
- The literal replacement keeps the source
number, the original selection order drives the added sequence, and extensions preserve their original case.
Literal replacement
- Input
- draft final.txt; draft notes.txt
- Options
- Replace literal draft with client-a and add suffix -approved.
- Action
- Preview and export CSV.
- Expected output
- client-a final-approved.txt and client-a notes-approved.txt with an old/new mapping.
- Explanation
- Only names and mapping data are handled; browser security prevents direct disk renaming.
Error or unsupported case
Output collision
- Input
- A.txt and a.txt with
lowercaseconversion - Expected error or limit
- Both would resolve to a.txt and the duplicate mapping is blocked.
- Safer alternative
- Change the numbering or prefix rule until every output name is unique and valid for the target operating system.
When not to use this tool
- Renaming files directly on disk or traversing folders
- Regex replacement or operating-system-specific reserved-name guarantees
Algorithm and assumptions
Rules execute in a fixed documented order over the selected filename list; extensions are separated, sequence padding is deterministic, and duplicate outputs are rejected before CSV export.
Input and output
Input is local filenames and rename rules. Output is an old-to-new preview plus downloadable CSV mapping.
Supported formats and behavior
- Prefix and suffix
- Literal find/replace and case conversion
- Sequential numbering with configurable start
Limits
- Does not rename or upload files
- No regular-expression replacement or folder traversal
Edge cases and common errors
- Rules can create duplicate names
- Files without extensions are supported
- Operating systems reserve some characters and names
Release testing
Checks cover extensions, no-extension names, numbering, replacement, duplicates, CSV download, clear, network privacy, and 390px use.
Privacy boundary
The input and result stay in this browser session. ZZP Box does not upload or store the values entered in this tool.
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