Convert a raw AAC file (.aac) to the more universally compatible MP3 locally in your browser. No upload.
Running locally on your device ...
Running locally on your device ...
0%
Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
A raw .aac file is a bare ADTS elementary stream with no surrounding container - unlike M4A, which wraps AAC in an MPEG-4 shell. Some recording apps and stream captures output exactly this raw format, which not every player opens.
This tool decodes the AAC stream and encodes it with libmp3lame to MP3 at the chosen bitrate - MP3 is understood by practically every device, car and player. AAC itself is usually considered slightly cleaner than MP3 at the same bitrate, but is less widely supported.
Since both formats are lossy, choose a bitrate at least at the level of the AAC source. Everything happens locally in the browser with ffmpeg.wasm, with no upload and no account.
| Input formats | AAC |
|---|---|
| Output format | MP3 |
| Batch processing | No |
| Processing | Locally in your browser (WebAssembly) |
| File upload | None |
Limitations: Both formats are lossy - a second round of compression costs additional, mostly small detail. One file per run.
No, the conversion runs entirely locally in the browser.
.aac is a raw ADTS stream with no container, .m4a wraps the same AAC audio in an MPEG-4 container with metadata.
At the same bitrate, AAC is usually considered slightly cleaner, but MP3 is supported by more devices.
Yes, there is the dedicated tool "Convert M4A to MP3" for that.
OGG to MP3 · Opus to MP3 · FLAC to MP3 · AIFF to MP3 · Strip metadata · Record audio · Audio speed · Find the BPM · Find the key · Edit MP3 tags