Convert MP3 to M4A online
Convert a MP3 file to M4A directly in your browser — the file is never uploaded to a server.
or click to select it
Convert an MP3 file to M4A (AAC audio) directly in your browser. Note that this doesn't improve audio quality — it's a lossy re-encode of an already lossy file — and its main use is Apple ecosystem compatibility.
Decodes the MP3's audio and recompresses it with the AAC codec inside an M4A container. Since this is a second lossy encoding pass on a file that already lost data when it was created as an MP3, there's no quality improvement over the original — at best, a tiny bit of extra loss from the double compression.
Use cases
- Create an iPhone ringtone: iOS requires M4A/M4R files and doesn't accept MP3 directly.
- Prepare an MP3 for import into GarageBand or for organizing in the Apple Music library, both of which prefer AAC/M4A.
- Adapt audio for Apple ecosystem apps or devices that only recognize M4A.
How it works
- 1
Upload your MP3 file
Drop the file in or select it from your device.
- 2
Click Convert
ffmpeg.wasm decodes the MP3 and re-encodes it as AAC inside an M4A container.
- 3
Download the M4A
Once it's done, download the resulting file.
Technical details
Runs ffmpeg.wasm in your browser, at a default bitrate of 192 kbps. This kind of lossy-to-lossy re-encode can introduce a small amount of extra generation loss, usually inaudible on music at reasonable bitrates, but technically the result is never more faithful to the original than the source MP3 itself.
Frequently asked questions
Does converting MP3 to M4A improve the sound?
No. It's a lossy re-encode of an already-lossy file; the result doesn't sound better than the original MP3 and, at worst, loses a touch more quality from the double compression.
Can I use the resulting M4A directly as an iPhone ringtone?
You need to rename the extension to .m4r and add it via iTunes/Finder or Settings — the audio file itself is already compatible.