Duplicate File Finder (SHA-256 Hash Compare)
Pick several files or a folder and files with identical contents are listed in groups. Files are first narrowed down by size, and only files of the same size are hashed with SHA-256, which keeps it fast. Files are processed in your browser and are never uploaded. To get the hash of a single file, use the File Hash Calculator.
🔒 Runs in your browser · Your data is never sent to a server
Drag and drop files here, or pick them with the buttons. Picking more adds to the list.
Choosing a folder includes every file inside it.
How to use
- Drag and drop files into the box, or use "Choose files" or "Choose folder".
- Only files of the same size are hashed with SHA-256, and files with identical contents appear in groups.
- Check the wasted space per group and in total, then clean up the unneeded files yourself.
- Save the list with "Copy results" or "Download CSV".
Notes
- This tool only finds duplicates; it never deletes anything. Use the listed paths to tidy up yourself.
- Files up to 256 MB each can be compared. Larger files are skipped.
- Only the contents (bytes) are compared. Files with different names or modified dates are still duplicates if their contents match.
- For folders, browsers only expose a relative path starting at the folder name, not the full path on disk.
Glossary
SHA-256
A 256-bit "fingerprint" computed from a file’s contents. Identical contents always give the same value, and changing even one byte gives a completely different one.
Wasted space
The space you would free by keeping one copy of identical files and removing the rest, calculated as size × (copies − 1).
FAQ
Are my files uploaded to a server?
No. Files are only read into your browser’s memory to compute SHA-256 and are never sent anywhere.
How are duplicates detected?
Files of the same size become candidates, and only those candidates are hashed with SHA-256. Files with both the same size and the same hash are treated as duplicates.
Can it delete the duplicates for me?
No. A browser page cannot delete files you picked, so use the listed paths to clean up yourself. You can copy the results or save them as CSV.
Does it work with very large files or many files?
Each file can be up to 256 MB. Whole files are read into memory to be hashed, so many same-sized files take a while; progress is shown on screen.
Why are files with different names reported as duplicates?
Only the contents are compared; names and modified dates are ignored. If every byte matches, the files are shown as duplicates whatever they are called.
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