Batch file renamer
Rename a whole set without guessing what the rule will do. Stack simple rules, inspect every proposed name and correct exceptions before downloading the copies.
Add files, shape the names, review and save the batch.
Make every name make sense.
Build a recipe on the left. Check every result on the right.
Before → after
Drop files or try the sample to see every proposed name.
See the names before you save.
Load a few sample files, then move a rule and watch the preview respond.
| # | Original | New name | Review | File actions |
|---|
Only your rename rules save automatically. Signed in, they save to your private account. Files, original names and one-off edits stay in this tab. Account saving
How to rename files in bulk
Add your files
Drop files into the studio or browse your device. Any file type works, up to 500 files and 512 MB per batch.
Build and review the recipe
Choose a starting recipe or stack your own rules. Every proposed name updates live. Edit exceptions and fix any name conflicts.
Save renamed copies
Download one file directly or a ZIP of the batch. You can also export a CSV map of original and new names.
Using the batch file renamer
The studio has two jobs: make a naming recipe and check its output. You can try the sample first, without choosing files.
Your files
Drop files onto the outlined area or press Drop files or browse to choose them. Adding more files keeps the ones already in the batch.
| Control | What it does |
|---|---|
| Drop files or browse | Adds any file type. The batch stops at 500 files or 512 MB total. Files over the remaining space are not added. |
| Try sample files / Try the sample | Loads three small text files so you can practise the whole workflow. It replaces the current file selection, but keeps your recipe. |
| Clear files | Removes the selected files and one-off name edits from this tab. Your recipe remains. |
Starting recipes and rule order
Starting recipes replace the current rule list. Tidy names cleans separators and case. Number a set keeps the name and adds a padded number. Numbers only replaces the name with 1, 2 and so on. Add today's date adds a date prefix. You can then edit, move or remove each rule.
Rules run top to bottom and change only the part before the extension. This makes a sequence applied after tidying different from one applied before it.
| Rule or control | Effect |
|---|---|
| Replace whole name | New name replaces the entire stem, without matching the original text. Enter video to turn this-is-file.mp4 into video.mp4. Leave it blank to keep the current stem. Each original extension stays intact. |
| Find & replace | Find sets the literal text to match, not a regular expression. Replace with sets its replacement for every match. Turn Match case on when IMG and img should differ. Leave Replace with empty to remove text. |
| Add prefix / Add suffix | Text to add goes before or after the stem. The extension stays at the end. |
| Sequence number | Numbers files in their batch order. Start at sets the first number; Digits pads it with zeros. Place number adds it before or after the name, or replaces the stem with Only the number. The last option ignores Separator. Set Digits to 1 for 1.mp4 instead of 001.mp4. |
| Change case | Changes the stem to lowercase, UPPERCASE or Title Case. The extension keeps its original case. |
| Tidy separators | Use between words chooses a hyphen or underscore. Runs of spaces, underscores and hyphens become one separator, trimmed from the edges. |
| Add a rule / Add | Select an operation, then press Add. A recipe holds up to 12 rules. Up and down arrows change order. The × button removes a rule. |
For a shared name with unique numbers, put Replace whole name before Sequence number. Enter video to get video-001.mp4, video-002.mp4 and so on. A shared name without numbering can create duplicates, which block the renamed download.
Only the recipe saves automatically. Signed in, those typed rule values save privately across your devices. Original filenames and individual edits remain in this tab.
Review every proposed name
Original and new names sit beside each other. Type into a New name field to handle one exception after the recipe runs. The edit stays through recipe changes. Press Use recipe name to reset it.
The row arrows move a file and change its sequence number. The row's × button removes that file. Search this preview and Issues only filter the table view; neither changes which files the download contains.
| Review mark | What to do |
|---|---|
| Changed / Unchanged | The new name differs from the original, or no rule affected that file. |
| Fix name | Correct an empty, duplicate, reserved, overlong or cross-platform invalid name. The renamed download is blocked until every issue is fixed. |
| Extension changed | You changed the full name by hand. Check the file after export because a new suffix did not convert its contents. |
Download the result and its name map
Download renamed file saves one selected file directly. For two or more, Download renamed ZIP builds a ZIP with the proposed names. No source file is overwritten.
Download name map saves a CSV with original name, new name and review state. Spreadsheet-like formula prefixes are escaped in that report. The map is a separate export and contains filenames, so review it before sharing.
Cancel stops ZIP creation and keeps your batch for another attempt. File and rule controls pause while the ZIP is being built. Your browser decides where downloaded copies are saved.
Focus mode
Press Focus mode to give the studio the viewport. Choose Narrow, Wide or Full in its Width control. Done, Escape or browser Back returns to the page with your batch intact.
Keyboard controls
Use normal form controls. There are no global shortcuts that interrupt browser or assistive technology keys.
| Key | Action |
|---|---|
| Tab / Shift + Tab | Move through the file picker, rules, row controls and download buttons. |
| Enter | Leave a proposed name field. Edits already update the preview as you type. |
| Space | Activate a focused button or checkbox. |
| Esc | Exit Focus mode without discarding your files or recipe. |
Limits and unsupported jobs
The tool accepts up to 500 files and 512 MB in one batch. ZIP creation needs device memory and may fail earlier on a small phone. Split a large set into smaller batches.
It does not read photo dates or document contents to choose names. Files are exported in one level; folder paths and filesystem timestamps are not preserved. The ZIP stores bytes without compression. It does not rewrite your source folder.
The extension means the final dotted part: archive.tar.gz keeps .gz. A leading-dot file such as .env has no extension. Today's date uses your device's local date, not a photo capture date.
The batch renaming guide compares browser, Finder and Windows methods, including when a desktop tool is a better fit.
Frequently asked questions
Can I rename multiple files online without uploading them?
Yes. This tool reads the filenames and builds the download in your browser. The file bytes do not go to floi for processing. Your originals stay on your device. Signed-in rename rules save automatically to your private account, but the files and original filenames do not.
Does changing a file extension convert the file?
No. The recipe preserves extensions. You can type a different full name into an individual row, but that changes only the label. A .png renamed to .jpg is still PNG data. Use a real converter when you need a different format.
What happens if two files get the same name?
Both rows are marked as conflicts and the renamed download is disabled. Names are compared without case, so Report.pdf and report.pdf also conflict. Change a rule, edit one proposed name or remove a file, then export.
Can I use it to bulk rename photos or PDFs?
Yes. The tool accepts any file type and preserves the original extension while its rules change the part before it. It does not read photo EXIF dates, PDF text or other file contents to invent a name.
How many files can I rename in one batch?
Up to 500 files and 512 MB total. The ZIP is assembled on your device, so available browser memory can still limit a large batch. A single renamed file downloads directly. Split a larger folder into smaller batches.
Can this rename the files already sitting in my folder?
A browser cannot silently rewrite files in an arbitrary folder. This tool downloads renamed copies, leaving the originals alone. For an in-place folder rename, use Finder, File Explorer, PowerShell or a desktop renamer after previewing the names.
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