Convert M4A to AAC
To convert M4A to AAC, add your .m4a file below and press the button: it's processed on your own device and you download the result, with nothing uploaded. It's free, needs no account, and works with files up to 500MB.
About converting M4A to AAC
M4A (.m4a) files can be converted to AAC entirely in your browser — no software to install, no file upload, and no account required. The conversion runs on a WebAssembly build of ffmpeg directly on your device.
Technical comparison
| M4A | AAC | |
|---|---|---|
| Category | audio | audio |
| Compression type | Lossy (AAC), or lossless via ALAC | Lossy |
| Typical file size | Small — comparable to MP3 at a given bitrate | Small — comparable to or smaller than MP3 at a given bitrate |
| Transparency support | N/A (audio) | N/A (audio) |
How to convert M4A to AAC privately
Every step below runs on a WebAssembly build of ffmpeg inside this browser tab. Your .m4a file is never uploaded to a server — there's no network request carrying it anywhere.
Add your M4A file
Drag and drop, or click to select, a file (.m4a). It's read straight from disk into browser memory — no upload step exists.
Convert locally
FreePrivateConvert converts it to AAC using a WebAssembly build of ffmpeg, entirely within this browser tab.
Download the result
Save your converted .aac file. It only ever existed in this tab's memory — closing the tab without downloading discards it completely.
Convert M4A to AAC with ffmpeg (command line)
Prefer the terminal? This is the exact ffmpeg command this page runs for you:
ffmpeg -i input.m4a -c:a aac -b:a 192k output.aac- -i input.m4a
- Your M4A file.
- -c:a aac
- Encode the audio as AAC.
- -b:a 192k
- Audio bitrate of 192k per second: high quality for AAC.
- output.aac
- The AAC file to create. ffmpeg picks the container from this extension.
Don't have ffmpeg installed? You don't need it: use the converter at the top of this page. It runs the same conversion on your own device, and your file is never uploaded.
FAQ
- Is my file uploaded anywhere?
- No. Your file is read and processed inside this browser tab and never leaves your device. You can confirm it in your browser's developer tools: the Network tab shows no upload.
- Does converting M4A to AAC reduce quality?
- AAC is lossy and M4A was already compressed, so this is a second lossy encode, at 192 kbit/s. That's high enough that most listeners won't notice a difference.
- Is there a file size limit?
- Yes: 500MB per file. There's no account and no limit on how many files you convert.
- What's the difference between M4A and AAC?
- M4A (MPEG-4 Audio) and AAC (Advanced Audio Coding) store data differently. M4A: lossy (AAC), or lossless via ALAC. AAC: lossy. AAC is MP3's successor codec — better sound quality at the same bitrate, and the standard audio codec for MP4 video and Apple's ecosystem.
- Why convert M4A to AAC?
- Common uses for AAC: Audio track in MP4/YouTube video; Apple Music and iTunes downloads; Streaming services optimizing for bitrate efficiency. More efficient compression than MP3 at equivalent bitrates, thanks to a more modern psychoacoustic model.
- What MIME type does a .aac file use?
- audio/aac, the standard type for Advanced Audio Coding.
- What is the ffmpeg command to convert M4A to AAC?
- Run: ffmpeg -i input.m4a -c:a aac -b:a 192k output.aac. This is the exact command FreePrivateConvert runs for this conversion, so you can use this page instead of installing ffmpeg: it runs the same conversion inside your browser.
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