Czkawka
FreeFinds duplicate files, near-identical photos and assorted junk
A duplicate and junk file finder written in Rust. Beyond byte-identical duplicates it finds **visually similar** images, acoustically similar music and similar videos, plus empty folders, empty files, temporary files, unusually large files and broken files.
Why we picked it
Duplicate files accumulate quietly: the same photos imported from a phone twice, three copies of one document in Downloads, backups of backups, chat-app-saved images alongside the originals. By the time you notice, it is often tens of gigabytes.
Czkawka — Polish for "hiccup" — is currently the best free tool in this space. 32,685 stars, MIT licensed, written in Rust, fast, and completely free with no feature limits, which matters because commercial software in this category typically scans free and charges to delete.
It finds more than a typical duplicate finder:
- Byte-identical files by hashing, comparing size first and then content. Exact and reliable.
- Visually similar images — its most valuable feature. The same photo at different sizes, different compression, with a filter applied, or a screenshot next to the original all hash completely differently but look identical to a human. Perceptual hashing catches these, with an adjustable similarity threshold.
- Similar music by audio fingerprint, catching the same track at different bitrates.
- Similar videos by frame comparison.
- Empty folders, empty files and temporary files — the debris of years.
- Broken files: images, archives and audio that open but are corrupt.
- The largest files, for quickly locating what is consuming space.
It ships two interfaces — the traditional GTK GUI and the newer Krokiet UI — plus a command-line version for scripting.
One warning deserves emphasis: the risk with this class of tool is not finding, it is deleting.
- Preview and sort before deleting anything, especially for similar images — you may legitimately want both a full-resolution original and a web-sized copy.
- It offers selection rules (keep newest, keep shortest path), but understand a rule before applying it rather than select-all-and-delete.
- Prefer "move to recycle bin" over permanent deletion, leaving yourself room to reconsider.
- Never clean system or program installation directories. Identical files inside applications are normal, and deleting them breaks software. Restrict cleanup to your own documents, pictures and downloads.
Used carefully it frees a substantial amount of space; used carelessly it deletes things it should not. Going slowly is worth it.