AAC (Advanced Audio Coding) is the modern standard used by Apple, YouTube, and most streaming services. It sounds better than MP3 at the same bitrate, but many older devices — classic car stereos, budget MP3 players, and legacy media software — only support MP3. This tool converts raw AAC files to MP3, processed entirely in your browser without any upload.
Drop files here
or browse to upload
Up to 200.0 MB per file
Upload your AAC file
Drop an AAC file. Note: M4A files (which are AAC in an MPEG-4 container) should use our M4A to MP3 converter instead. This tool handles raw .aac files.
Select bitrate
Since AAC is more efficient than MP3, match or exceed your source AAC bitrate for best results. If your AAC was 128 kbps, use 192 kbps MP3 to roughly match perceived quality.
Convert
Click Convert. FFmpeg decodes the AAC and re-encodes as MP3 using LAME. The process is quick for typical AAC file sizes.
Download the MP3
The MP3 plays on devices and software that don't support AAC. Import into any audio editor or player.
AAC is the audio codec; M4A is a file container that holds AAC audio. An M4A file IS AAC audio, just wrapped in an MPEG-4 container. Raw .aac files and .m4a files both contain AAC audio, but have different file structures. iTunes and iPhone Voice Memos use .m4a; broadcast and streaming applications sometimes use raw .aac. Use our M4A to MP3 converter for .m4a files.
AAC is technically superior to MP3 — at 128 kbps, AAC sounds equivalent to MP3 at 160–192 kbps. Apple adopted AAC for iTunes and iPhone for this reason. But for legacy hardware compatibility, MP3 remains the most universally supported format. If your playback device supports AAC, keep the AAC file.
This tool converts one file at a time per session. For batch conversion of large libraries, FFmpeg on the command line (free) handles thousands of files with a single command: ffmpeg -i input.aac output.mp3. Our browser tool is optimized for quick one-off conversions without software installation.
A rough equivalence guide: 96 kbps AAC ≈ 128 kbps MP3; 128 kbps AAC ≈ 192 kbps MP3; 192 kbps AAC ≈ 256 kbps MP3; 256 kbps AAC ≈ 320 kbps MP3. Match or exceed these to minimize perceptible quality loss in the double-encoding process.
Car stereo AAC support varies by manufacturer and model year. Many head units built before 2015 only support MP3 (and sometimes WMA). The AAC codec requires a license fee, which budget manufacturers avoid by sticking to MP3. Converting your music library to MP3 ensures it plays in all car audio systems.
Something not working? Report a bug
