AAC to MP3

Convert a raw .aac file to MP3 right here, with nothing uploaded. AAC to MP3 is the quick fix when a player, a car stereo or an editing app refuses the file, and it takes about as long as reading this sentence for a short clip.

How it works

  1. 1.Add AAC files

    Only .aac files go in this box; AAC inside an .m4a file has a page of its own.

  2. 2.Set the bitrate

    128 kbps for talk, 192 kbps for most music, 256 or 320 kbps if you want headroom.

  3. 3.Convert AAC to MP3

    Everything happens in a Web Worker on your device. The first run downloads the engine once.

  4. 4.Download

    Save single MP3s, or one ZIP for the whole batch.

Settings

  • Bitrate for the batch, plus a per-file override that re-converts just that file.
  • Artist, album and year tags; the title comes from each file name.
  • Trim by start and stop time, and match loudness across files.

AAC without a container

AAC (Advanced Audio Coding) was standardised by MPEG as the successor to MP3, and it is the codec behind most M4A and MP4 audio.

A .aac file is the bare stream, usually in ADTS frames, with no MP4 wrapper around it. Voice and screen recorders, some phones and saved radio streams produce files like this.

Without a container there is no index for the whole file, so some players can't show the length or seek properly, and plenty simply don't list .aac files.

Converting means a second lossy encode. AAC is efficient, so choose an MP3 bitrate at least as high as the source — 192 kbps is a safe bet.

Privacy and file limits

Your files stay on your computer or phone. The page loads a WebAssembly encoder, and all decoding and encoding happens in your browser — there is no server step to wait for and nothing to delete afterwards.

On a computer you can add up to 15 AAC files at once, 200 MB each and 500 MB in total. Phones get 50 MB per file and 120 MB per batch, because a mobile tab has far less memory to work with.

Related converters

AAC inside an .m4a? Use M4A to MP3. To pull the soundtrack out of a video, MP4 to WAV extracts it uncompressed, and WAV to MP3 on the home page turns that into an MP3.