Convert MP3 to M4A in your browser
AAC in an MP4 container, which is what Apple software means by M4A. Your MP3 is already lossy, so this is a second pass and the bitrate default reflects it.
Sample audio: Prelude in C major, BWV 846 (J.S. Bach), performed by Kimiko Ishizaka. Dedicated to the public domain (CC0). See sample-audio-LICENCE.txt for details.
or browse your device. Everything is processed on this device
No MP3 to hand?
If nothing actually requires an M4A, lowering the bitrate on the MP3 you already have does the same job without adding a lossy generation.
Compress MP3 insteadHow to convert MP3 to M4A
A track, an album or the folder your library lives in. Nothing is uploaded, so the size of the batch is a question for your laptop rather than a server.
That is the setting that keeps a second lossy pass honest. Lower it only if the file has to fit somewhere specific, and expect music to show it.
An .m4a holding AAC that Music.app, iTunes, iOS, macOS and most modern car systems will import without complaint.
What is an M4A, and will this improve my MP3?
M4A is not a codec. It is an MP4 container holding audio and nothing else, and what is inside it is almost always AAC, which is what this page writes. Apple chose the extension so that a file of music would not be confused with a film, and that convention is why Music.app, iTunes and iOS all name M4A while the rest of the world says AAC or MP4. An .m4a is not DRM protected; that was .m4p, and it has not been sold in well over a decade.
AAC is a better codec than MP3, and the answer to the obvious next question is still no. Converting cannot improve an MP3, because the MP3 encoder threw audio away when the file was made and the AAC encoder is working from what came back out of the decoder. What AAC being better does buy you is that the second pass costs less than re-encoding to MP3 would at the same bitrate, which is why 192 is enough here.
So convert when something wants an M4A: a ringtone workflow that needs an .m4r, a Music.app library you would rather keep in one format, a device or upload form that names AAC. If nothing is asking, the MP3 you have is the file with fewer generations of loss in it, and keeping it is the better choice.
MP3 to M4A FAQ
Is M4A the same as AAC?
Effectively, yes, for a file like this. M4A is an MP4 container carrying an audio track, and the track this page writes is AAC. Software that asks for AAC, MP4 audio or M4A will all take the file the same way.
Will the M4A sound better than the MP3?
No. AAC is the stronger codec, but it is being handed audio an MP3 encoder has already stripped, and it cannot restore what is missing. At 192 kbps the second pass is very hard to hear; it is still a second pass.
Can I make an iPhone ringtone from this?
This is the first half of it. A ringtone is an .m4r, which is an M4A trimmed to under 40 seconds and renamed, so convert here, trim in any editor, then change the extension. Nothing on this site writes .m4r directly.
Do the artist and album survive?
Yes, unless you turn on "Strip tags and cover art", which is off by default here. ID3 tags are rewritten as MP4 metadata, which is what Music.app reads, so the track files itself correctly on import.
Why is my M4A a similar size to the MP3?
Because size is bitrate times duration and the bitrate is what you chose, not what the codec is capable of. AAC would sound better than MP3 at 192 from a lossless master; from an MP3 you are mostly buying the container that Apple software wants.
Are my MP3 files uploaded to convert them?
No. The MP3 is decoded and the M4A is written by your own browser, in this tab. There is no upload endpoint in the site for a file to go to, which you can check in your network tools: convert something and watch that no request carries it. Disconnect from the network after the page loads and it still works.
Related
Same format joins the queue. Anything else re-routes to its own tool.