Convert video and audio online for free
Convert a video or audio file you already have on your device into another format, right in your browser. Nothing gets uploaded anywhere: the whole process runs locally, private and free.
Why use this converter?
Available conversions
How do you convert a file online?
Choose the conversion you need (for example, MP4 to MP3).
Select the file from your device.
Hit 'Convert' and wait for the browser to process the file.
Download the result: it saves straight to your device.
This converter changes the format of a video or audio file you already have saved on your device, with no software to install and nothing uploaded anywhere online. If you don't have the file yet and need to download it from a social network first, use our video downloaders; this tool is the next step, for converting a file you already have.
How it works: everything happens in your browser
The converter uses ffmpeg, the same engine behind many professional editing programs, compiled to run inside the browser via WebAssembly. When you pick a file, it never travels to any server: it's processed locally, right in the tab you have open, and the result downloads straight to your device. That means more privacy — nobody else sees your file — and zero server cost for us, so it can genuinely be free.
Available conversions
For now we offer these 5 conversions, the most requested ones:
- MP4 to MP3: pulls the audio out of an MP4 video.
- MKV to MP4: turns an MKV video into an MP4 container that plays on any device.
- WebM to MP4: converts WebM videos (typical of browsers) into universal MP4.
- MOV to MP4: converts MOV videos (the iPhone/QuickTime format) into MP4.
- M4A to MP3: converts M4A audio into MP3, the most compatible format.
Limits worth knowing about
Because it runs in your browser, the real ceiling is your device's memory and processing power, not a cap we've set. Very large files (above 2 GB) or very long videos can take several minutes or run out of available memory, especially on phones with limited RAM. For heavy video re-encodes (changing resolution, heavy compression) a dedicated desktop program will still be faster; this converter is built for quick, one-off format changes.
Real privacy, not just a claim
Since the file never leaves your device, there's no upload, no server receiving it, and no copy left anywhere except on your own machine. It's the most private way to convert a sensitive or personal file.
Frequently asked questions
Does the file really never get uploaded to a server?
Correct. The conversion runs on ffmpeg compiled to WebAssembly, executing inside your own browser. The file is read, processed and downloaded without ever leaving your device — we never see or store its contents.
Is it free?
Yes, completely free. Since the whole process happens in your browser instead of on our servers, converting a file costs us nothing, so there's no artificial usage limit and no sign-up needed.
What conversions can I do?
Right now we offer 5: MP4 to MP3, MKV to MP4, WebM to MP4, MOV to MP4 and M4A to MP3. That covers the most common needs: pulling audio out of a video and unifying different video containers into MP4.
Why does it take so long with large files, or freeze up?
The real limit is your own device's memory and processing power, not something we've imposed. Files of several GB or very long videos can take minutes or run your browser out of memory, especially on phones. If that happens, try a computer instead.
Do I need to install anything, or does it work on mobile?
Nothing to install: it works in any modern browser (Chrome, Firefox, Edge, Safari) with WebAssembly support, on a computer or on Android or iPhone.