Does converting M4A to FLAC improve quality?

No. Most M4A files hold AAC, which is lossy, and FLAC can only keep what the AAC still has. The FLAC sounds the same as the M4A and is several times larger. An M4A with Apple Lossless inside converts to FLAC without loss, but it does not get better either.

Is M4A to FLAC lossless?

The FLAC step is: the file stores the decoded audio as 16-bit or 24-bit samples without changing them further. Whether the whole path is lossless depends on the M4A. From AAC, the loss already happened when the M4A was made. From Apple Lossless at its own bit depth, nothing is removed.

Why does my M4A not convert in Chrome?

It probably holds Apple Lossless. Chrome, Edge and Firefox do not decode ALAC; Safari does. The line under the file says Apple Lossless when the page can read the header. Open the page in Safari, or convert the file in the Music app first.

Why is the FLAC so much bigger than my M4A?

AAC keeps only a small part of the audio data, about 0.9 MB a minute at 128 kbps. FLAC keeps all of the decoded audio, so a minute of CD-quality stereo is roughly 5 to 6 MB. The extra size does not mean extra detail.

Are my M4A files uploaded?

No. Your browser decodes each M4A and the FLAC encoder runs on the page, so the recordings stay on your device. The page counts ordinary analytics events, such as how many files were converted and the level chosen, but never the files or their names.

M4A to FLAC Converter

Need FLAC for a music library, a hi-fi player or an archive, and your files are M4A from iTunes, a phone or a Mac? Drop up to 10 of them here. Each one shows whether it holds AAC or Apple Lossless before you convert, so you know what the FLAC will and will not be. The files stay on your device.

Drop your M4A files here or click to browse

M4A and other audio files. Up to 10 files, 100 MB and 30 minutes each.

The files are processed in your browser and are not uploaded.

How to convert M4A to FLAC

The page reads each M4A's header first, so the list tells you what is inside before anything is converted.

1
Add the M4A files
Drop up to 10 at once. Under each name you see its length, its sample rate and a line saying whether it is AAC or Apple Lossless.
2
Keep Auto and level 5
Auto writes AAC at 16 bits and keeps Apple Lossless at its own depth. Same as the file keeps the sample rate. Level 5 is the reference encoder's default; every level gives the same sound.
3
Convert and save
Each file is decoded by your browser and encoded to FLAC in turn. Download them one by one, or all of them as a ZIP when there are two or more.

Only need a file that plays everywhere? Try M4A to MP3. For an uncompressed file an editor opens, use M4A to WAV.

Does converting M4A to FLAC improve the sound?

It depends on what is inside the M4A, and most M4A files hold AAC. AAC is lossy: when the file was made, the encoder threw away detail it judged you would not hear. FLAC is lossless, so it stores whatever it is given without changing it. Given a decoded AAC, it stores the decoded AAC. The detail that was removed is not in the M4A any more, and no converter can put it back.

So an AAC M4A turned into FLAC sounds the same as the M4A and takes several times the space. It is still worth doing when something needs FLAC, or when you are going to edit the audio: MDN notes that lossy compression is compounded by recompressing, and FLAC stops that chain at the step you are on.

Apple Lossless (ALAC) is different. It is lossless itself, so ALAC to FLAC moves the full original audio from one lossless format to another. Keep the bit depth on Auto so a 24-bit file stays 24-bit. One limit: only Safari decodes ALAC, and this page reads the samples through Safari's decoder, so it does not promise a bit-for-bit match with the ALAC. For an archive that needs a checksum match, check the result with a desktop tool.

AAC or Apple Lossless: what you get

The line under each file on this page tells you which one it is.

Inside the M4A	Lossy?	Opens in	The FLAC is
AAC (most M4A files)	Yes	Chrome, Edge, Safari; Firefox when the system provides AAC	The decoded AAC, stored without further loss
Apple Lossless (ALAC)	No	Safari only	The full audio, lossless to lossless

Browser support from MDN's Web audio codec guide, read 6 November 2026. Apple's Voice Memos on Mac offers Compressed or Lossless recordings, so one Mac can produce both kinds.

Why the FLAC is bigger than the M4A

Per minute of CD-quality stereo (44.1 kHz). AAC stores a small fraction of the audio data; FLAC stores all of what was decoded, a little packed.

File	One minute
M4A, AAC at 128 kbps	938 KB
M4A, AAC at 256 kbps	1.8 MB
WAV, 16-bit	10.1 MB
FLAC, 16-bit (estimate)	5.0 MB to 6.1 MB

The FLAC range uses MDN's figure of up to 40 to 50 percent smaller than uncompressed audio; your files may land outside it. That is about 5.5 to 6.6 times a 128 kbps M4A. 1 MB = 1,048,576 bytes.

When M4A to FLAC makes sense

A library or player that wants FLAC
Many music servers, car stereos and hi-fi players are built around FLAC. Converting once puts the M4A files in the same format as the rest.
Moving Apple Lossless off Apple
ALAC plays well on Apple devices and poorly elsewhere. FLAC carries the same lossless audio to players and apps that never opened ALAC.
Before you edit
Cutting or mixing an AAC file and saving it as AAC again loses a little more each time. Convert to FLAC first and edit that; make the small copy at the end.
Not to save space or to fix sound
For AAC files, FLAC is larger and sounds the same. If a smaller file is the goal, keep the M4A.

Is the M4A a recording of a conversation?

FLAC keeps the sound safe, but finding what someone said still means listening. For your next meeting or interview, ParrotNotes records it on your phone, then transcribes and summarizes it.

Get Started Free

Related tools

M4A to FLAC FAQ

Sources

M4A to FLAC Converter

How to convert M4A to FLAC

Add the M4A files

Keep Auto and level 5

Convert and save