About the Bulk File Renamer
Renaming files one by one is slow and boring. This tool lets you add many files and change all their names at once. Find and replace text (with optional regular expressions), add a prefix or suffix, change the letter case, replace spaces, add a counter with the digits you choose, and set the extension to lower or upper case. A table shows the old and new name of every file as you type, and warns you when two files would end up with the same name or a name would be empty. A web page cannot rename files on your disk, so you download the same files with their new names in a ZIP file and unzip it. Your files are not uploaded; they are read inside your browser.
Updated October 2026
How to use the Bulk File Renamer
- 1Add your files with Select files or by dropping them.
- 2Set your rules: find and replace, prefix, suffix, case, numbering.
- 3Check the preview table for the new names and any warnings.
- 4Fix any warnings, for example by adding numbering.
- 5Press Download renamed files (ZIP) and unzip it.
Planning your names
Good file names sort well and say what is inside. Start with a date in year-month-day form (2026-10-08) so the files sort in time order, then a short description, then a number if needed. Avoid spaces, which can cause trouble in links and command lines, and avoid very long names, which some systems cut off.
Try the rules on the preview first. It is easy to change a rule and see the result at once, and nothing is changed until you download.
Recipes
- Photos: find IMG_, replace with holiday-, then add a number after.
- Documents: lowercase, kebab-case and spaces to underscores.
- Remove a word: find it and leave the replacement empty.
- Add a date: use Add after the name with -2026-10.
- Change .JPG to .jpg: set the extension to lowercase.
- Remove numbers from the end: regular expression \s*\d+$ with an empty replacement.
Related tools
Pack the renamed files with Create ZIP File, check what is inside a ZIP with Unzip Files, or convert between archive types with the Archive Converter. For text inside the names use the Case Converter. Picture details can be inspected with the EXIF Data Viewer before you rename photos by date.
Features
- Find and replace with optional regular expressions
- Prefix, suffix and numbering with padding
- Lower, upper, title, kebab and snake case
- Spaces to underscores, extension case
- Live old and new name table
- Warns about duplicates and empty names
- Private, nothing is uploaded
Frequently asked questions
Can it rename the files on my computer directly?
No. Browsers do not let a web page change the names of files on your disk. You get a ZIP with the same files under their new names.
How do I number files like photo-001, photo-002?
Tick Add a number, set Start at 1, Digits to 3 and the separator to a dash. Use Add before the name with photo for the prefix.
How do I use a regular expression?
Tick Find is a regular expression and type a pattern. In the replacement, $1 is the first group in brackets. For example, find (\d+) replace -$1.
What if two files get the same name?
They are flagged in red and the download button is disabled until you fix it, for example by adding numbering.
Which characters are not allowed in file names?
Slash, backslash, colon, asterisk, question mark, quotes, angle brackets and the vertical bar. The tool replaces them with an underscore.
Is there a limit on files?
Up to 500 files and about 400 MB in total, because the files are packed in your browser's memory.
Are my files uploaded?
No. They are read and zipped on your device.