Last reviewed August 23, 2026

How to Find Exact Duplicate Files Privately

Understand size prefiltering, cryptographic hashes, wasted-space reporting, and why similar photos are not exact duplicates.

Exact duplicates have identical bytes

Matching names, dates, or dimensions are insufficient. Exact duplicates contain the same byte sequence; a photo with changed metadata, recompression, or edits is a different file even when it looks identical.

Size first, SHA-256 second

Files with different byte sizes cannot be exact duplicates, so OpenFileTools groups by size before hashing. Only same-size candidates receive SHA-256, reducing unnecessary reads while providing final exact-byte confirmation.

Review duplicate groups

Choose files or a supported folder, run the comparison, then inspect every path in each group. Wasted space assumes one copy is retained and the remaining identical copies could be removed elsewhere.

The browser does not silently delete files

Ordinary browser file inputs grant read access, not arbitrary filesystem deletion. This version identifies duplicates and leaves deletion to your file manager so the decision remains explicit and recoverable.

Privacy and troubleshooting

Hashes and file bytes remain in the tab. If visually identical photos are not grouped, compare their metadata or encoding: exact hashing intentionally does not perform perceptual similarity matching.

  • The selection is limited to 500 files and 200 MB.
  • Keep backups before deleting important data.
Try the browser tool

Work with your file locally.

Open Duplicate File Finder