Add your files, set rules for find and replace, case, prefixes, suffixes, and numbering, check the preview, and download the renamed files as a ZIP.
This tool runs entirely in your browser. What you enter is never sent anywhere.Your input is never sent anywhere.
DetailsDrag and drop the files you want to rename
You can select several files at once
Batch Rename Files with Five Stackable Rules
Renaming a folder of photos or documents one file at a time is slow and easy to get wrong. This renamer combines five rules: find and replace, case change, prefix and suffix, sequence numbers, and extension change. Turn on any combination and see every new name before anything is created.
The preview lists each old name next to its new name. You can edit any name by hand, uncheck files you want to leave out, and sort the list before numbering. If two files would end up with the same name, the tool adds (2), (3), and so on.
When the names look right, download a ZIP of the renamed files. Renaming and ZIP creation happen in your browser, and your original files stay as they are.
Photos, Deliverables, and Messy Downloads: Common Uses
Camera and phone photos
Turn names like IMG_4021.jpg into something readable, such as Vacation_001.jpg, using find and replace plus sequence numbers.
Client deliverables
Apply a naming convention to a batch of files before you send them: a project prefix, a version suffix, and consistent numbering.
Uploads that reject spaces or capitals
Some web forms, CMS media libraries, and servers handle spaces and capital letters badly. Convert names to lowercase and replace spaces with underscores or hyphens first.
Cleaning up downloads
Remove copy markers such as " (1)" from names like Invoice (1).pdf, or strip a shared piece of text from dozens of exported files at once.
From Upload to ZIP in Four Steps
- Drag your files into the drop area or choose them with the file picker. You can add more files at any time.
- Switch on the rules you need and set them: find and replace, change case, prefix or suffix, sequence numbers, or a new extension.
- Check the preview. Edit a name directly, or uncheck a file to leave it out of the ZIP.
- Click Rename and download ZIP, then unzip the download to get your renamed copies.
Note: Files are read and zipped in your browser. The originals on your computer are not renamed.
Before You Run It
- Only names change. File contents are not modified.
- Rules run in a fixed order: find and replace, case change, prefix and suffix, sequence numbers, then extension. A prefix or suffix is added after the case change, so it keeps the capitalization you typed.
- Sequence numbers follow the sort order shown in the list and skip unchecked files.
- A name you edit by hand in the preview stays fixed when you change the rules. Reset all rules and edits clears those manual edits.
- Duplicate names get (2), (3), and so on. The check ignores upper and lower case.
- Names containing \ / : * ? " < > | are flagged. Windows does not allow these characters, and a slash would put the file inside a folder in the ZIP.
Rule Examples: Before and After File Names
Typical settings and the names they produce. Each row uses one rule on its own.
| Goal | Rule and setting | Before | After |
|---|---|---|---|
| Number files from the start | Add sequence numbers (at start, 3 digits, start at 1, separator _) | IMG.jpg | 001_IMG.jpg |
| Swap a piece of text | Find and replace, Plain text: IMG_ → Photo_ | IMG_0001.jpg | Photo_0001.jpg |
| Replace spaces with underscores | Find and replace, Regex: \s+ → _ | My File Final.docx | My_File_Final.docx |
| Lowercase everything | Change case: lowercase | Report_FINAL.pdf | report_final.pdf |
| Add a version tag | Add prefix or suffix: suffix _v2 | report.xlsx | report_v2.xlsx |
| Reformat with a capture group | Find and replace, Regex: IMG_(\d+) → Photo-$1 | IMG_0042.jpg | Photo-0042.jpg |
| Remove a copy marker | Find and replace, Regex: \s\(\d+\)$ → (empty) | Invoice (1).pdf | Invoice.pdf |
Turn on several rules to combine them. They run in the order listed in the notes above.
Naming Tips: Regex, Numbering, and Illegal Characters
A few details that help you get the names you expect on the first run.
Why a browser-based renamer keeps your files local
This tool reads your files with JavaScript on the page and builds the ZIP there, so no server is needed to do the renaming. That matters when the files are client documents or personal photos.
Regex basics for file names
\d+ matches a run of digits and \s+ matches spaces. ^ and $ anchor a pattern to the start or end of the name. In the Replace box, $1 and $2 insert the parts you wrapped in parentheses, so IMG_(\d+) with Photo-$1 turns IMG_0042 into Photo-0042.
Patterns run on the name without its extension unless you tick Include the extension. If the pattern is invalid, an error message appears and the rule is skipped until you fix it.
How numbering order works
Numbers are given in the order the list is sorted. Choose Order added, Name (A–Z), Name (Z–A), or Modified date before you check the result. Name sorting reads digits as numbers, so file2 comes before file10. Unchecked files are not counted, so the numbers stay continuous.
Characters that cannot appear in file names
Windows does not allow \ / : * ? " < > | in file names. In a ZIP, a slash is read as a folder separator, so the file would end up inside a folder. The preview marks names that contain any of these characters.
Common Mistakes and How to Fix Them
Running a regex without checking the preview
A pattern that matches more than you meant can change every name, and you only notice after unzipping the download.
💡 See the solution▼
Changing the extension to a different file type
Setting a new extension only changes the text after the dot. A PNG renamed to .jpg is still a PNG, and some apps may refuse to open it.
💡 See the solution▼
Numbers in the wrong order
Sequence numbers follow the sort order of the list, which may not be the order you expected.
💡 See the solution▼
A suffix or number that lands after the extension
With Include the extension ticked, the whole name is treated as one piece, so a suffix produces names like photo.jpg_final.
💡 See the solution▼
Expecting your original files to be renamed
The download is a ZIP of renamed copies. The files on your computer keep their old names.
💡 See the solution▼
Questions About Renaming, Regex, and ZIP Downloads
Q.Does the renamer change what is inside my files?
A. No. It only changes names. Each original file is added to the ZIP as it is, under its new name. The files on your computer are not touched, so you get renamed copies when you unzip the download.
Q.How do I replace spaces with underscores in file names?
A. Turn on Find and replace, choose Regex, enter \s+ in the Find box, and enter _ in the Replace box. The preview shows the new names right away. Use - instead of _ if you prefer hyphens.
Q.How do I make all file names lowercase?
A. Turn on Change case and pick lowercase. By default the extension is left alone, so Photo.JPG becomes photo.JPG. Tick Include the extension to lowercase it too (photo.jpg).
Q.Can I use it without knowing regular expressions?
A. Yes. In Plain text mode, special characters such as . and ( are treated as ordinary text, and every match in a name is replaced. Matching ignores upper and lower case unless you tick Match case. Switch to Regex only when you need patterns.
Q.How do I add sequence numbers to file names?
A. Turn on Add sequence numbers, then choose whether the number goes at the start or the end of the name. You can set the first number, the number of digits (1 to 6, padded with zeros), and the separator. Numbers follow the order of the list, and unchecked files are skipped when counting.
Q.How many files can I rename at once?
A. The tool does not set a limit. Files are held in your browser's memory while the ZIP is built, so the practical limit depends on your device and the total size of the files.
Q.Can I rename only some of the files?
A. Yes. Uncheck any file in the preview and it is left out of the ZIP. You can also tick Skip files whose names don't change to keep untouched files out of the download.
Q.What happens if two files end up with the same name?
A. The second file gets (2) before its extension, the third gets (3), and so on. The check ignores upper and lower case, because many systems treat Photo.jpg and photo.jpg as the same name. Adjusted rows show a Duplicate fixed badge in the preview.
Q.Can I change file extensions in bulk?
A. Yes, for example .JPEG to .jpg. This only changes the text of the extension. It does not convert the file to another format, so a PNG renamed to .jpg is still a PNG.
Q.Does the ZIP keep each file's modified date?
A. The tool sets each ZIP entry's date to the file's last-modified time. Whether that date is kept after extraction depends on the program you use to unzip.
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