Duplicate File Finder
Select a batch of files and find exact duplicates by comparing their actual content — not just filenames — entirely in your browser.
About this tool
Choose several files — perhaps a folder of photos, downloads or documents you suspect has copies lurking in it — and this tool computes a SHA-256 content hash for each one using your browser's own built-in cryptography support. Two files with completely different names but identical content will always produce exactly the same hash, while two files with the same name but different content never will, so hashing is a reliable way to spot true duplicates regardless of how they've been named or where they came from. Files are hashed one at a time with a simple progress indicator, which keeps the logic straightforward and avoids overloading the browser on a large batch; for a handful of files this is instant, and even a few hundred typically finishes in a few seconds. Matching files are grouped together under "Duplicate groups", and everything else is listed as unique. Nothing is uploaded anywhere — every byte stays on your device, and the hashes are only ever used to compare the files against each other in this one session.