Find duplicate files without installing anything
Photos, videos, audio and documents. Point this page at a folder and it tells you what is repeated, by comparing the contents of every file — never its name.
100% private. Your files are processed on your device and never uploaded to any server. You can disconnect from the internet after this page loads and watch it keep working. Handles folders with tens of thousands of files. Files over 2 GB cannot be compared, because the browser cannot load them into memory in one piece.
What makes FileDupes different: you install nothing
Every duplicate file finder on the market is a program you have to download, install and often pay for. This one is not. It is a web page that works on your files using your own computer's power.
Nothing to download
No installer, no adware, no toolbars that appear out of nowhere. You open the page and it is already working.
Your files never travel
The folder is read from your disk and the analysis runs on your machine. Disconnect from the internet and see for yourself: it keeps working.
No permanent permissions
You grant access to one folder, and that permission dies when you close the tab. Nothing stays installed watching your disk.
Works on any machine
Windows, Mac or Linux, it makes no difference. If the browser opens, the tool runs. There is no version to update.
The file name does not matter
This is the most common confusion, so let us be blunt: the tool never looks at what a file is called. You could have the same photo saved as holiday.jpg, IMG_0042.jpg and untitled (3).jpg, in three different folders, and all three would come out grouped together.
What gets compared is the content. Every file gets a SHA-256 fingerprint, a 64-character number summarising its bytes. If two files produce the same fingerprint, they are the same file. Change a single bit and the fingerprint changes completely.
That fingerprint is indifferent to format, which is why it works just as well on a video, a song, a PDF or a spreadsheet as it does on a photo.
One detail that keeps it fast
Reading a 4 GB file end to end just to fingerprint it takes time. So before anything else, files are grouped by exact size: if no other file in the folder weighs exactly the same, it cannot have a twin and there is no need to read it. In a folder full of video, that single trick is the difference between seconds and half an hour.
What it detects for each file type
It is worth being honest about the limits, because not every format allows the same thing:
- Any file — exact, byte-for-byte copies. Video, audio, documents, archives, executables. No margin for error.
- Images — all of the above, plus the same photo across different files: re-compressed, resized, or back from a WhatsApp round trip.
- Video and audio — exact copies only, for now. Recognising the same song at two different qualities means analysing the sound itself, which is a far heavier engine. We would rather not promise it before we have it.
- Documents — exact copies only. Two PDFs with the same text but produced by different programs are different files, and the tool treats them as such.
How it decides two photos are the same
The visual comparison happens in two stages, and that is what avoids the false positives almost every tool suffers from.
First, a perceptual hash proposes candidate pairs. It is fast but imprecise — a folder of screenshots fools it easily, since they are all pale with thin text — so it never decides anything on its own.
Then comes the real comparison: each candidate is reduced to a 32×32 grayscale grid and the correlation between the two is measured. That number, as a percentage, is what you see. Because it is normalised by contrast, it ignores brightness and compression changes but collapses the moment the content differs.
Two more guards: images with different aspect ratios are never grouped, because a crop is not a duplicate; and images without enough detail are only grouped if they are literally the same file.
Nothing gets deleted
The tool never calls a delete operation. Everything you select is moved into a subfolder called _duplicates inside the folder you scanned. You open it, look through it, and delete it yourself when you are sure. If something went wrong, dragging the files back takes seconds.
Frequently asked questions
Does it work for more than photos?
Yes. Exact-copy detection works with any format: video, audio, PDF, Word, Excel, archives, anything. The visual comparison, which recognises the same photo at another size, is images only.
Does it find duplicates with different names?
Yes, and the name is never used. Contents are compared through a SHA-256 fingerprint of the bytes. Two files with the same fingerprint are the same file even if they are named differently and sit in different folders.
Do I have to install anything?
No, and that is the whole point of this tool. It runs inside the browser you already have. No program is downloaded, nothing is left on your machine, and there is no version to update.
What exactly does the percentage mean?
It is how closely two images match when compared pixel by pixel on a 32×32 grid. 100% with the "same file" label means identical byte for byte. 99% means the same photo at another compression or size.
What if it groups things that are not the same?
Set the sensitivity to "Strict". Groups are recalculated instantly without re-reading the folder. And the percentage is visible on every file: if you see a 94% on something that does not belong, uncheck it.
Are my files uploaded anywhere?
No. The browser reads the folder from your disk and all the work happens on your machine. Disconnect from the internet after the page loads and the scan still finishes.
Which browsers get the full version?
Desktop Chrome, Edge, Brave and Opera can read and write the folder you choose. Firefox and Safari can read it, so you still get the full report and the CSV export, but you move the files yourself.
How many files can it handle?
Tens of thousands. The analysis is spread across several parallel workers, and the size pre-filter avoids reading files that cannot possibly have a twin.