Watch it not upload your file
Convert a file and watch the browser count what left your device.
- Add
- Adjust
- Make
- Keep
How to use this tool
- Add your files — drag them onto the page or choose them. They stay on your device.
- Add a file and pick any conversion — the panel shows the browser's own performance timeline while the work happens.
- Watch the bytes-sent counter stay at zero from the moment you press convert. That is the whole point.
- Press “Process files” and download the results, individually or as one ZIP.
About this tool
Convert a file and watch the browser count what left your device. Zero. The same numbers a Network tab would show, measured while the work happens. Everything is analysed and produced on your own device — nothing is uploaded anywhere, and you can verify it: the tools keep working even offline.
Privacy & limitations
The counter reads this browser's own performance timeline — the same evidence your Network tab shows, not our claim about it. WebAssembly engine downloads (about 31 MB, once, for video/audio) are listed as downloads TO you; the count that stays at zero is bytes sent FROM you. You can also go offline after the page loads and keep converting.
Last updated:
Frequently asked questions
How do I know a file converter is not uploading my files?
Open the Network tab in your browser’s developer tools and convert something. You will see the page and its code load, and after that nothing carrying your file. The stronger test is to disconnect from the internet after the page has loaded: anything that still converts was never using a server.
What are the requests it does show?
The page, its stylesheet and code, and for video or audio the WebAssembly build of FFmpeg. Those are programs being downloaded to you, which is the opposite direction from your file being uploaded, and they are listed rather than hidden because pretending a 31 MB download did not happen would undermine the point.
Could a page hide an upload from this?
Not from the browser’s own timeline, which is where these numbers come from. That is also why the honest version of this page is possible at all: a converter that uploaded your file would be publishing the evidence.