Mono to Stereo Converter
Duplicate a mono recording into both channels of a stereo file.
Fill in the form and press “Convert to stereo” to see the result here.
How to use it
- 1Choose your file, or drag it onto the upload area.
- 2Set the options. Every setting is a fixed choice, which is what keeps the conversion safe to run.
- 3Press the button. The job is queued and the page shows it move through waiting, processing and ready.
- 4Download the result. Both your upload and the result are deleted once you have it.
About the Mono to Stereo Converter
This produces dual mono: identical audio in both channels. It does not create a stereo image, because the information for one was never recorded.
It is still worth doing when a player or platform insists on two channels, or when audio is only coming out of one side.
Questions people ask
What actually does the work?
FFmpeg, the same open-source toolchain most video software is built on. It runs as a separate process with a fixed argument list, a time limit and no network access. Nothing from your filename or your settings is ever passed to a shell.
Why does this one take longer than the other tools?
Media work is genuinely expensive: a re-encode reads and writes every frame. The job is queued so that a busy moment slows things down rather than taking the site out, and the page shows where your job is in that queue.
What happens to the file I upload?
It is stored under a random name that is not guessable, processed by an isolated worker, and deleted as soon as you download the result - and in any case automatically after 60 minutes. Uploads are never indexed, shared or used for anything besides producing your result.
Is it free, and do I need an account?
Yes, it is free, and there is no account, no sign-up and no watermark on the result. The project is funded by optional donations.