Add your files
Drop one MP3 or two hundred. Batch conversion is not a paid feature here.
Convert MP3 to MP4
An audio track has to be uploaded to YouTube or another platform that will not accept an audio file.
SafeConvert engineFreeNo sign-upBatch supported
Where the streams already fit the target container this is a lossless remux, which is close to instant. Otherwise it re-encodes, which in a browser is slow — keep it under a few hundred MB and send long videos to the cloud engine.
Waiting for files/Engine: on-device/Network requests made: 0
What actually changes
MP3 and MP4 are not the same picture in two wrappers.
A video track has to be invented, because MP4 as these platforms accept it needs one. A static image, the cover art, or a rendered waveform is encoded as video alongside the audio.
Worth knowing first
A still image encodes almost for free with H.264, since nothing changes between frames, but a moving waveform does not. Choosing an animated visualiser can multiply the output size by twenty for content nobody is watching.
Questions
MP3 to MP4, answered
What resolution should the still be?
1280 by 720 is enough for an audio upload. Higher resolutions cost encoding time and buy nothing.
Can I use my album art?
Yes. Embedded cover art can be used as the still frame automatically.
How to convert MP3 to MP4
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Choose your settings
MPEG-4 Video is lossy, so the quality control decides the trade between size and fidelity.
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Download
Converted and deleted the moment it finishes. Never written to permanent storage.