M4A to AAC Converter
Convert M4A to AAC free — no upload, no signup
To convert M4A to AAC, drop your M4A audio files into the box below and click Convert. Fylo converts with ffmpeg running inside your browser, so nothing is uploaded and there's no signup or watermark. Extract the AAC stream from M4A without re-encoding.
Drop audio files here
or tap to browse · paste with Ctrl+V · add many at once
Your files never leave your device
Advanced
How to convert M4A to AAC
Add your M4A files
Drag and drop M4A files into the box or tap to choose them. The converter engine (about 31 MB) downloads once, the first time you convert.
Pick a bitrate
192 kbps suits music and 128 kbps or less suits speech. Sample rate and mono/stereo are under Advanced.
Convert and download
Click Convert, then download each AAC file or all of them as one ZIP.
Why convert M4A to AAC?
Some streaming encoders and broadcast tools need a raw AAC (ADTS) stream rather than an MP4 container.
What happens when you convert M4A to AAC?
Fylo copies the AAC audio out of the M4A container — no quality loss, near-identical size.
How does Fylo convert M4A to AAC?
Fylo decodes the AAC (or ALAC) audio in the M4A with ffmpeg compiled to WebAssembly and encodes it with FFmpeg's AAC encoder at 160 kbps, written as a raw ADTS stream. Both formats are lossy, so each conversion discards a little detail — start from the highest-bitrate M4A you have. A 3-minute song is ≈ 3.6 MB at 160 kbps as M4A and ≈ 3.6 MB at 160 kbps as AAC. The original sample rate and channel layout are kept unless you change them under Advanced.
What's the difference between M4A and AAC?
M4A is an MPEG-4 container that holds only audio — usually AAC, or Apple Lossless (ALAC). Apple popularised the extension with the iTunes Store in 2003; iPhone Voice Memos and many podcasts also use it. Audiobooks often use the related .m4b extension.
AAC (Advanced Audio Coding) was standardised in 1997 as part of MPEG-2 and later MPEG-4, designed to replace MP3. It achieves better quality at the same bitrate, especially below 128 kbps. A .aac file is usually a raw ADTS stream; the same audio inside an MP4 container is called M4A.
Learn more: M4A format guide · AAC format guide
| Property | M4A | AAC |
|---|---|---|
| Compression | Lossy (AAC) or lossless (ALAC) | Lossy |
| Typical bitrate | 128–256 kbps | 96–256 kbps |
| 3-minute song | ≈ 3.6 MB at 160 kbps | ≈ 3.6 MB at 160 kbps |
| Tags and cover art | Yes (full, with cover art) | Limited in raw .aac (full in M4A) |
| Compatibility | Apple devices, Android, Windows 10+, browsers | Very wide: Apple, Android, YouTube, browsers |
| Best for | iTunes/Apple Music libraries, voice memos, audiobooks | Efficient music and video soundtracks |
| Introduced | 2003 | 1997 |
Frequently asked questions
Is M4A to AAC lossless?
Yes, the audio is copied, not re-encoded.
Will the raw AAC keep tags?
No — raw AAC streams can't store tags.
Is my M4A file uploaded to a server?
No. Fylo runs ffmpeg, the same engine used by professional video tools, compiled to WebAssembly inside your browser. Your M4A file is read directly from your device and never sent anywhere.
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