MP3 vs M4A

Choose MP3 for music and podcasts for any device. Choose M4A for Apple devices and streaming. Both compress the same way; the difference is compatibility and ecosystem.

MP3M4A
CompressionLossyLossy
Metadata
Open / royalty-free-
Defined by-Apple / MPEG
Since1993-
Best formusic and podcasts for any deviceApple devices and streaming

MP3

The universal lossy audio format.

M4A

AAC audio in an MP4 container. Apple's default; better than MP3 at the same bitrate.

Questions

MP3 or M4A: which is smaller?

It depends on the content; see our measured benchmarks on the conversion pages.

Can I convert MP3 to M4A?

Yes, in your browser, nothing uploaded.

And M4A to MP3?

Yes, as well.