Convert AAC to M4A
Convert AAC to M4A right in your browser — free, private, nothing is uploaded. One-click re-encode for compatibility.
Convert AAC to M4A →Free · Private — runs in your browser, nothing is uploaded
AAC is the codec behind M4A files, streaming services and much of broadcast audio; as a bare .aac stream it carries the same lossy audio without the MPEG-4 wrapper — and without proper tag support.
M4A wraps AAC audio in an MPEG-4 container — the format iTunes and Apple Music use. AAC squeezes better quality than MP3 out of the same bitrate, at the cost of slightly narrower support.
Converting AAC to M4A is a compatibility move: both formats are lossy, so the goal isn't quality — it's producing a file that fits Apple devices and small high-quality files. Expect the sound to stay essentially the same, with a small second round of encoding loss.
AAC vs M4A
| AAC | M4A | |
|---|---|---|
| Compression | lossy — some detail traded for size | lossy — some detail traded for size |
| Codec / container | raw AAC (Advanced Audio Coding) stream | AAC audio in an MPEG-4 container |
| Typical file size | small — similar to MP3 at the same bitrate | small — like MP3, often better quality per byte |
| Best for | streams, broadcast audio and recorder output | Apple devices and small high-quality files |
| Strength | modern lossy codec, efficient at every bitrate | better quality than MP3 at the same bitrate |
| Watch out for | bare .aac streams carry no metadata and trip up some players | slightly less universal than MP3 |
| Compatibility | the codec is everywhere, but fewer apps open bare .aac files | excellent on Apple devices; broad elsewhere |
How the conversion works
- Choose your AAC file (up to 10 MiB). The button above opens the converter with M4A already selected as the target format.
- Pick a bitrate between 32 and 320 kbps — the default 192 kbps is transparent for most material, and values outside the range are clamped.
- Run the conversion and download the result — the output keeps your filename with a .m4a extension. Everything happens locally: the page runs ffmpeg compiled to WebAssembly, so your audio is never uploaded to a server.
What to expect
Generation loss stacks. Re-encoding lossy AAC audio with another lossy codec adds a second round of loss. Keep the M4A bitrate at or above the original's and avoid repeated round-trips between formats.
Embedded album art is dropped along the way: cover images ride along as a video stream, which audio-only outputs like M4A can't carry.
FAQ
Will converting AAC to M4A make my audio sound worse?
Marginally, in principle: both formats are lossy, so the re-encode adds a second generation of loss. At 192 kbps or higher it's rarely audible, but keep the original AAC and avoid converting back and forth.
What bitrate should I pick for the M4A file?
The converter accepts 32–320 kbps and defaults to 192 kbps, which is a good balance for music. Use 128 kbps for voice where size matters and 256–320 kbps for archiving; when re-encoding from AAC, match or exceed the source's bitrate to limit further loss. Values outside the range are clamped.
Is my AAC file uploaded when converting to M4A?
No. The page downloads an ffmpeg WebAssembly build once, then converts your file locally in the browser tab — the audio never leaves your device. Input files up to 10 MiB are supported.