Duplicate File Detector
Find identical files in a folder by content, not name.
About Duplicate File Detector
Pick a folder and the tool hashes every file to group byte-identical duplicates, no matter what they are called. It shows how much space you would reclaim; deletion is left to you, since the browser never gets write access.
Same name and same size is a guess. Two different photographs from one camera can share both, and identical files often have completely different names.
Hash every file and group the ones that are genuinely identical.
- Processed on your deviceEverything you open or type here is handled by this page and never uploaded anywhere.
- No queue, no limitsNothing waits on a server, so the only limit is your own hardware.
- No account neededNo sign-up and no email address required.
How Duplicate File Detector works in your browser
Files are first grouped by size, because two files of different lengths cannot be identical. Every file that shares its size with another is then read in full and digested with SHA-256 in this tab. Files with matching digests are byte-for-byte identical whatever they are called and wherever they sit.
That gives the property name-and-size matching cannot: no false positives, and no missed duplicates hiding behind a different filename. Files are read in this tab and never transmitted, which is the difference from a cloud duplicate finder — those must receive your entire folder in order to tell you two files match.
Hashing is not free. Every byte of every candidate file has to be read, so a folder full of same-sized files takes time proportional to their total size, on your own hardware.
When to use it
Clearing space by finding photographs imported more than once. Reconciling a folder that has been copied and edited in two places. Checking whether a download you already have is the same file. Deduplicating personal documents without uploading them to a scanner.
Read more about this
Frequently asked questions
Does it match on file names?
No, on content. Every file is hashed, so byte-identical copies are grouped no matter how differently they are named.
Will it delete the duplicates for me?
No, deliberately. It shows the groups and how much space you would reclaim; deciding which copy to keep is a judgement only you can make.
Are my files uploaded to be compared?
No. Hashing happens in your browser, which is why you can safely point it at a folder of personal documents.