Convert AAC to MP3
Turn raw AAC streams into MP3 files that every player will open.
Drop a file to start
Runs in your browser. Nothing is uploaded.
A bare .aac file is an ADTS stream: the audio with just enough framing to be played, and none of the container that an .m4a or an .mp4 wraps around it. They come out of broadcast tools, stream rippers and some recorders, and they are the files most likely to be met with a shrug by ordinary software.
MP3 is the exchange format that nothing refuses, which is the whole point of this page. AAC is the better codec of the two at equal size, so the conversion is for compatibility rather than quality — keep the setting high and the second lossy pass stays inaudible.
Decoding uses the browser’s own AAC support and encoding uses LAME compiled to WebAssembly, so both ends run on your machine. Files convert one after another with nothing uploaded, no size cap and no account.
Step by step
- 1Drop in your AAC files.
- 2Choose how much quality to keep.
- 3Press Convert, then download.
Questions
What is the difference between .aac and .m4a?
The container. An .m4a wraps AAC audio in an MP4 file with room for tags and chapters; a .aac is the raw stream. Both hold the same kind of audio.
Will the file get bigger?
Often slightly, at matched quality, because MP3 needs more bits than AAC to sound the same. That is the cost of the compatibility.
Can I go the other way?
Not on this page. The general converter takes anything to anything, including back to AAC.