How to use it
- Add your files. Drop MP3 files on the page or use Choose files. Folders and ZIPs work too.
- Check that MP4 is selected. MP4 is already chosen on this page.
- Adjust options if you need to. Quality, size and other settings appear when the format has them.
- Convert and download. Press Convert; with several files, “Download all” gives you one ZIP.
What happens to your file
Video formats need a picture, so the sound is put into an MP4 with a moving waveform of the audio. The sound itself is kept at high quality.
About MP3 and MP4
MP3: MP3 is the universal audio format: every phone, car stereo and app plays it.
MP4: MP4 is the most widely supported video format: phones, browsers, TVs and every editor play it.
Questions
Is my MP3 file uploaded?
No. The conversion runs inside this browser tab, and the MP4 is created on your device. Nothing is sent to a server.
Is there a file size limit?
No fixed limit: files are processed by your device, so very large videos depend on its memory. Computers handle several GB; phones are best with smaller files.
Can I convert several MP3 files at once?
Yes. Drop as many as you like, a folder or a ZIP; “Download all” saves every MP4 in one ZIP.