About this tool
Choose a case style, preview the new filenames, and download copies. Characters without uppercase or lowercase forms are preserved. A separate option controls whether extensions change too.
How to use
- Select the files to organize.
- Choose lowercase, uppercase, title case, or sentence case.
- Enable extension case changes if needed, then check the preview and conflicts.
- Download renamed files or a ZIP.
Features
- Supports lowercase, uppercase, title case, and sentence case.
- Changes only the base name by default, with a separate extension case option.
- Preserves Unicode text and checks for conflicts between names that differ only in case.
Case and filenames
- Your browser does not modify the original files on your computer. This tool creates downloadable files with new names.
- Converting only the base name of MyPhoto.JPG to lowercase produces myphoto.JPG. Enabling extension changes produces myphoto.jpg.
- Characters without case distinctions remain unchanged. Case mappings in some languages may change the number of characters.
- File systems handle capitalization differently, so names that differ only in case may still conflict.
Limits
- Select up to 1,000 files at a time. When downloading multiple files as a ZIP, their combined original size must not exceed 100 MiB.
- Filenames must not include folder paths. Adjust the rules if a name is too long, empty, or conflicts with another name.
- File contents stay unchanged; only the download name or ZIP entry name changes. Keep your originals and check the preview.
Privacy
All files are processed only in your browser and are never uploaded to a server.
File names, entered text, and results are processed only in your current browser. Your input is not saved automatically. Download any results you want to keep before clearing the tool or leaving the page.
FAQ
Will the extension's capitalization change?
Not by default. Extensions follow the case rule only when you enable the extension case option.
How are characters without uppercase and lowercase forms handled?
They remain unchanged and are not removed during case conversion.
What is natural sorting?
It compares numbers by their numeric value, giving an order such as file1, file2, file10. Use Sort Filenames to arrange the list.
Are Windows filenames case-sensitive?
Behavior depends on the file system and settings. Many common setups are case-insensitive, so this tool checks for potential conflicts between names that differ only in case.
Can the browser rename the original files on my computer?
No. This tool creates downloads with new names. Your original files are not renamed, moved, or overwritten.
How do I get the processed files?
Review the original and new names first. Download a single file directly, or download multiple files as a ZIP and extract the renamed copies.
Will the file contents change?
No. Renaming only changes the download name. The original bytes are preserved: images are not re-encoded, and text encoding is not changed.