Convert FLAC to M4A
Turn a FLAC into an M4A that an iPhone or a Mac will play. Apple has never supported FLAC on the device side, so a lossless library is invisible to the phone it is meant to be listened on. Because FLAC is lossless, the AAC encoder works from the original audio — this is a first-generation encode, not a copy of a copy.
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Up to 50 MB. Deleted automatically after 30 minutes.
What it does
- A first-generation AAC encode from lossless audio
- Plays natively on iPhone, iPad and Mac
- Roughly a quarter the size of the FLAC
- No watermark and no sign-up
How to use FLAC to M4A
- 1
Add the FLAC
Drop the file in or choose it from your computer, up to 50 MB, which covers most single tracks.
- 2
Convert
The FLAC is decoded losslessly back to samples, and those samples are encoded as AAC in an MP4 container.
- 3
Keep the FLAC
The M4A is the listening copy for the phone. The FLAC stays as the library.
A library the phone cannot see
FLAC is the format people rip collections to when they want the archive to be exact, and it is very good at that. What it is not is something an iPhone will play. Apple never implemented FLAC on iOS, macOS support arrived late and awkwardly, and Apple's own lossless answer is ALAC — a different codec doing the same job inside their ecosystem.
The practical result is a collection sitting on a hard drive that is perfect and unreachable from the device it exists to be heard on.
How it works
The FLAC is decoded back to its original samples — losslessly, so this step adds
nothing and removes nothing — and those samples are encoded as AAC inside an MP4
container, which is what an .m4a file is.
That order matters. Because the source is lossless, the AAC encoder is working from the actual recording rather than from whatever a previous encoder left behind. It is a first-generation encode, which is the best AAC can do.
What you are trading
Size for exactness, deliberately. A FLAC is typically around half of raw audio; an AAC is around a tenth. On a phone with a finite amount of storage and a library measured in albums, that difference decides how much of the collection travels with you.
The audio genuinely is not the same afterwards. Whether that is audible depends on the material, the equipment and the listener, and for most people in most situations it is not. The point is that the loss is confined to the copy, because the FLAC is still there.
ALAC, if everything is Apple
There is a middle option worth knowing about. ALAC is Apple's lossless codec — same idea as FLAC, supported natively across their devices, and it discards nothing at all. It is also roughly the same size as the FLAC, which is to say several times the AAC.
That makes it the right choice for moving a library between Apple machines, and the wrong one for filling a phone. Most people end up with a lossless archive at home and AAC copies on the device, which is what this conversion produces.
Do not delete the FLAC
It is the master. Every future format — a better codec, a higher bitrate, a device that finally reads FLAC — has to come from it, and once it is gone every conversion starts from what the AAC already discarded.
Examples
An album for an iPhone
The commonest reason. iOS will not play FLAC, so a lossless library has to be converted before any of it reaches the phone.
A lossless rip for Apple Music's library
Apple's own software imports M4A without argument and refuses FLAC, so this is the format the library expects.
Frequently asked questions
Why will my iPhone not play FLAC?
Because Apple never implemented it on the device. macOS gained some support in recent years and iOS remains awkward about it, so a FLAC library is effectively invisible to the phone. Apple's own lossless format is ALAC, which is a different codec solving the same problem, and the ecosystem was built around AAC for everything else.
Is this better than converting FLAC to MP3?
At the same file size, generally yes — AAC is the more efficient codec and the difference shows most at lower bitrates. It is also what Apple devices handle natively. MP3 remains the safer choice for a car stereo or an older player, so which is better depends entirely on what is going to play it.
Am I losing quality?
Yes, by design. FLAC is lossless and AAC is not, so this discards audio permanently in exchange for a file roughly a quarter the size that an iPhone will play. Whether you can hear it is a separate question and for most people on most equipment the answer is no. Keep the FLAC and the loss stays confined to the copy.
Should I use ALAC instead?
If everything that will play the file is Apple, ALAC is worth considering — it is lossless, so nothing is discarded at all, and Apple software handles it natively. The trade is size: an ALAC is about the same as a FLAC, several times an AAC, which matters on a phone. Use ALAC to move a library between Apple machines and AAC to actually carry it around.