Convert an .m4a recording or music file to .flac when your audio library, project, or recipient requests FLAC. This free M4A to FLAC converter processes one file at a time, with no account or software installation required. Upload the file and start the conversion. Once it finishes, download the FLAC copy.
Check what your M4A contains before deciding what the result means. AAC and ALAC can both use the M4A extension, but AAC is lossy and ALAC is lossless. A FLAC output does not, by itself, establish that the original recording was lossless.
M4A and FLAC: what changes during conversion?
M4A identifies an audio container, while the codec inside determines how the sound is represented. This page decodes the source audio and encodes it as FLAC. Simply changing the filename extension would not perform those steps.
| Property | M4A input | This tool's FLAC output |
|---|---|---|
| Extension | .m4a | .flac |
| Audio encoding | Commonly AAC or ALAC | FLAC |
| Compression | Lossy AAC or lossless ALAC | Lossless compression |
| Sample precision | Depends on the source codec | Depends on the decoded source and conversion |
| Bitrate | Depends on the source | Varies with the audio; no fixed bitrate setting |
| Main purpose | Existing recording or library file | Audio for a destination accepting FLAC |
FLAC preserves the integer PCM samples given to its encoder, as described in the FLAC features documentation. That property cannot reconstruct information missing from the source before conversion begins.
When an M4A to FLAC conversion is useful
Move an ALAC file into a FLAC library
If a library or playback workflow uses FLAC, converting an ALAC M4A can provide the expected file type while retaining decoded PCM samples when their precision, sample rate, and channels remain unchanged. Check those properties before replacing a library copy. Keep the original until you have also checked tags and artwork.
Deliver audio to a project that requests FLAC
A collaborator may ask for FLAC assets for an editing or analysis project. Confirm the required sample rate, bit depth, and channel layout first, then inspect the downloaded result against those requirements. This page offers format conversion, without controls for selecting a delivery specification.
Make an AAC recording usable in a FLAC workflow
A voice recording or audio export may only be available as AAC in M4A. Converting it can satisfy a FLAC input requirement, but the file remains derived from lossy audio. When archiving it, note that the file was converted from lossy AAC. If the destination already accepts your M4A, conversion may be unnecessary.
How to convert M4A to FLAC online
- Upload one M4A file. Choose or drag in a
.m4afile no larger than 200MB and no longer than 30 minutes. Wait for the file checks and upload to complete. - Start the conversion. FLAC is already the output format on this page. Start the task and wait for the uploaded audio to be processed.
- Check and download the FLAC. Preview the completed result if your browser supports it, download the
.flacfile, and open it in the application that will use it.
Finish downloading a cloud-stored source to your device before uploading it. The converter does not import a sharing link or connect to a music account. This page accepts .m4a files. Changing the extension of an .mp4 or .m4b file does not change its contents or guarantee that it meets this page's upload and decoding requirements.
Can you convert M4A to FLAC without losing quality?
For an AAC source, conversion decodes the audio that has already undergone lossy compression, then encodes the decoded audio as FLAC. It cannot recover the detail discarded during AAC encoding. A larger file or a 24-bit output display is not proof of improved sound or of a high-resolution original. Keep the AAC source if it is the best original you have.
For an ALAC source, lossless conversion to FLAC can retain PCM sample values when bit depth, sample rate, and channels are preserved. Supported 16-bit and 24-bit ALAC sources can produce corresponding FLAC outputs. That does not mean every M4A variant has been guaranteed identical, or that the entire file, including metadata, stays unchanged.
To verify that an ALAC conversion preserves every sample, compare the PCM samples decoded from the original and the result. Matching file properties and listening alone are not enough.
Check the source codec in a player's file information before comparing results. Use the same listening setup and comparable volume. A source that began as a lossy recording cannot become an original lossless master by passing through ALAC or FLAC later.
Check precision, playback, and library information
Look for FLAC as the output codec, then compare duration, sample rate, channel count, and bit depth with your requirements. The page has no bit-depth, sample-rate, channel, or compression-level selector. FLAC bitrate varies with the audio being compressed.
An AAC source may also produce a FLAC labeled 24-bit. The 24-bit label only describes how the output stores audio; it does not establish the original recording's precision or prove that it has never undergone lossy compression. For an ALAC archive, check the original and output properties before deciding whether the new copy meets your preservation needs.
Also inspect titles, artist names, artwork, and any chapter information you rely on. Complete metadata transfer is not guaranteed. Correct audio playback and a fully preserved library entry are separate checks; conversion does not rebuild missing tags or chapters.
Why the FLAC file can be larger
FLAC is compressed audio, but its compression is lossless. AAC generally discards information to use less space, so converting AAC to FLAC often increases file size. That extra storage does not indicate recovered detail.
ALAC and FLAC are both lossless, and neither extension guarantees the smaller result for a particular recording. Duration, sample precision, channel count, audio content, and compression behavior all matter. Silence and simple sounds may compress differently from dense music or noisy recordings, even with matching sample rates.
Use the actual downloaded size when planning storage or delivery. There is no target-size control or fixed reduction percentage. The original must fit the upload limit first: a file over 200MB cannot be submitted because you expect its FLAC copy to be smaller.
Input checks and playback
The page normally checks the input M4A's duration in the browser before upload. Some encodings, including ALAC in some browser environments, may fail this step even when another application can play the file. Check that the original is complete and try another browser if duration reading fails. If conversion has finished but the output will not preview, download it and check it in a FLAC-compatible player.
Frequently Asked Questions
Is this M4A to FLAC converter free?
Yes. No account or credits are required. Each task accepts one .m4a file within 200MB and 30 minutes, using the preset conversion settings.
How do I know whether my M4A contains AAC or ALAC?
Open its audio properties in a player or media-information tool and look for the codec name. The .m4a extension alone cannot distinguish lossy AAC from lossless ALAC.
Can converting AAC M4A to FLAC restore lost sound quality?
No. FLAC cannot reconstruct audio detail removed by AAC compression. It creates a FLAC copy of the available decoded audio, without turning the source into an original lossless recording.
Can I convert M4A to FLAC without losing quality?
It depends on the source codec. Supported 16-bit and 24-bit ALAC can retain PCM samples when bit depth, sample rate, and channels are preserved. AAC cannot regain information lost during its earlier encoding. Neither case guarantees complete metadata transfer.
Does a 24-bit FLAC prove my original was high resolution?
No. An AAC input may also produce 24-bit FLAC. That label describes the result's sample storage, not the original recording's precision or whether its history includes lossy compression.
Can I choose 16-bit FLAC output or a compression level?
No. There is no selector to force 16-bit FLAC or set a compression level. Output precision depends on the decoded source and conversion. The page also has no sample-rate, channel, or target-size controls, so check the saved file against your requirements.
What if the input or output will not preview?
If the page reports that it cannot read the M4A's duration, check that the original file is complete and try another browser. If a completed FLAC result will not preview, download it and check it in a FLAC-compatible application.