Free · Plan better extensions for many files

File Rename Plan Maker

Find names that do not match their bytes and download a safe rename plan without changing files.

  • Real magic-byte check
  • Private in your browser
  • JSON and CSV report

Open local files

The file stays in this browser tab. Detection uses its binary signature, not just its name.

file-type · local
Drop files hereUp to 50 files, 100.0 MB each

Files stay in this tab. The checker reads bytes but never opens or runs the file.

ResultReading the safe sample
Reading the signatureThe file is not opened or run.

A useful hint, not proof. A matching signature does not prove that a file is complete, valid, or safe. This tool does not scan for viruses.

Three simple steps

How to use it

  1. Choose the files you may want to rename.
  2. Check each current and suggested name.
  3. Download the plan and rename only files you trust.

Your files stay on this device

file-type reads the binary signature inside this browser tab. Bookify does not upload, save, open, or run the file. The result is a best-effort hint, not proof that a file is valid or safe.