Bulk File Renamer
Preview bulk renames with find/replace, sequences, case conversion, prefix/suffix.
How to Use
- Drop the files you want to rename. They're listed with their original names on the left.
- Apply renaming rules: find/replace text, add prefix or suffix, change case (lower/UPPER/Title), insert a numeric sequence (001, 002, 003...).
- The preview column on the right updates live as you adjust rules — verify before downloading.
- Click "Download as ZIP" to get all renamed copies in a zip archive.
- Original files on disk are never modified; you get renamed copies to download.
- Use the "Copy mapping" button to grab the old→new list for use in your own scripts (mv, rename, PowerShell).
| Original | New name |
|---|
Rule order
About the Bulk File Renamer
The Bulk File Renamer is a simple, free helper for image, audio and file tasks that runs entirely on your own device. Preview bulk renames with find/replace, sequences, case conversion, prefix/suffix.
How it works
Type in what you have, and the answer shows up right away. Change anything and it updates by itself. Everything runs in your browser, so it is fast and nothing you type is sent away.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
Will my original files be modified?
No. The browser can't directly rename files on disk for security reasons. Instead, this tool reads the files and produces renamed copies in a downloaded ZIP. Your originals are untouched. To rename in place, you'd need a desktop tool (Windows Renamer, Bulk Rename Utility, mv on Linux/Mac, PowerShell) — but the mapping output from this tool feeds directly into those.
How do numeric sequences work?
Pick a starting number, padding width (3 = 001, 002, ... or 4 = 0001, 0002, ...), and step (usually 1). Files are numbered in their listed order — drag to reorder before downloading. For non-sequential numbering (skip every other, custom starting point), you can adjust step or starting number.
Can I undo a rename?
If you've only downloaded the ZIP, yes — your originals are untouched. If you've replaced your files with the ZIP contents, you'd need to keep a backup of the originals to undo. The Copy mapping output documents the old→new mapping so you can write a reverse script if needed.
What about file extensions?
By default, extensions are preserved through all rename operations (the rules apply to the basename only). Disable that toggle to apply rules to the entire filename including extension if needed (rare, but useful for changing all .jpeg → .jpg, etc.).
Will it handle Unicode filenames?
Yes — JavaScript handles Unicode strings natively. Files with accented characters, CJK names, or emoji rename correctly. The downloaded ZIP preserves Unicode names; some older OS file systems may transliterate or replace unsupported characters on extraction.
Are files uploaded?
No. Reading and renaming happens entirely in your browser. Sensitive filenames (project codes, client names, internal product names) stay on your device. The downloaded ZIP is created locally.
How do I use the Bulk File Renamer?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Does it cost anything or need an account?
No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.
Is anything I type uploaded?
No. The tool works entirely on your device, so the values you enter never leave your browser.
Common Use Cases
Photo import normalization
Rename camera files from IMG_4321.jpg to vacation-2026-001.jpg in bulk.
Project cleanup
Standardize filenames across a project folder — consistent prefix, padding, and naming convention.
CMS and asset library prep
Rename files to URL-friendly slugs (lowercase, kebab-case) before uploading to a CMS or static site.
Music and media library
Rename audio or video files with track numbers and consistent naming for media-server cataloging.
Preparing for cloud sync
Some cloud services have filename restrictions; rename to remove problematic characters before upload.
Sequential ID assignment
Number a folder of receipts, expense docs, or invoices sequentially for filing or accounting.
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