What is the difference between FLAC and M4A?

FLAC compresses audio losslessly to roughly half the size of WAV, with the original samples fully recoverable. It supports proper metadata tagging, making it the standard choice for archival ripping and audiophile libraries. M4A is an MPEG-4 container carrying AAC audio. It is Apple's standard format for music and voice memos, and delivers noticeably better quality than MP3 at the same bitrate, especially below 160kbps.

Will I lose anything converting FLAC to M4A?

Yes — M4A is lossy, so some detail is discarded permanently in exchange for a much smaller file. A FLAC is already about half the size of the equivalent WAV, so expect roughly a fivefold reduction from here. At sensible bitrates most people cannot hear the difference on ordinary playback equipment. Keep your FLAC original as the master, because you cannot get back what the encoder throws away.

Anything to watch out for with M4A?

M4A is the container; AAC is the codec inside it. The same container with a .m4b extension is used for audiobooks with chapter markers. An .m4a file can also hold Apple Lossless (ALAC) rather than AAC, which is why file size varies wildly between two files with the same extension.

What bitrate should I use?

For music, 192kbps MP3 or 128kbps Opus is the point where most people stop hearing a difference from the source. For speech and podcasts you can go much lower — 96kbps MP3 or 64kbps Opus is transparent for voice. Going above 256kbps on a lossy codec mostly just makes the file bigger.

What should I know about starting from FLAC?

FLAC is losslessly compressed, so everything in the original recording is still present and can be re-encoded any number of times without compounding loss. More broadly: FLAC compresses audio losslessly — typically to 50-60% of the WAV size — with the original samples recoverable bit-for-bit. It is the standard format for archival ripping, audiophile distribution and anywhere a master needs to survive future re-encoding without generational loss.

When is M4A the right choice?

M4A suits: apple ecosystem playback; better quality than MP3 at the same file size; voice memos and recordings destined for a phone. It is the wrong choice when older hardware that predates AAC support.

Is there a file size limit?

No hard limit — the constraint is your browser's memory. Files under 50MB convert in a few seconds. Larger files work but take longer, and a browser tab typically has 250-500MB to play with, so very large batches are better split into smaller groups.

Does this work on mobile?

Yes. The drop zone falls back to your phone's file picker, and the conversion runs on-device exactly as it does on desktop. Large files are slower on a phone because there is less CPU and memory available, but nothing about the workflow changes.

Convert FLAC to M4A (AAC)

Convert a lossless FLAC library to M4A for phones, cars and anything short on storage. Keep the FLAC as your master. Free, in your browser, no upload.

Drop audio files to convert

WAV, MP3, M4A (AAC), AAC, OGG, Opus, FLAC

Files stay on your device. Open DevTools' Network tab to verify.

MP3/AAC/Opus and decoding compressed input use browser WebCodecs; available in modern browsers only.

Overview

Why convert FLAC to M4A (AAC)

FLAC is already compressed — losslessly, to roughly half the size of WAV — so this is not about saving space in the abstract. It is about fitting a library onto a phone, or feeding a player that will not take FLAC. Converting to M4A discards detail permanently, so keep the FLAC: it is your master, and you can re-encode from it any number of times without compounding loss.

Comparison

FLAC vs M4A (AAC): what actually differs

FLAC compared with M4A (AAC) across encoding, fidelity, file size and support.
Attribute	FLAC	M4A (AAC)
Full name	Free Lossless Audio Codec	MPEG-4 Audio (AAC)
Encoding	Binary	Binary
Fidelity	Lossless — bit-for-bit identical to the source on decode	Lossy — more efficient than MP3 at equivalent bitrates
Typical size	Roughly 50-60% of the equivalent WAV	Roughly 20-30% smaller than MP3 at perceptually equal quality
Support	All modern browsers and players; Apple added support in iOS 11.	Every Apple device, Android, modern browsers, most car systems.

How to

How to convert FLAC to M4A (AAC)

01
Drop your FLAC file
Drag one or more FLAC files onto the drop zone above, or click to browse. Files stay on your device — there is no upload step.
02
Convert to M4A
convert.now parses the FLAC and writes it out as M4A in a Web Worker, so the page stays responsive even on large files. Nothing is sent anywhere.
03
Download the result
Download the M4A file, or a zip of all of them for a batch. Filenames are preserved, with the extension changed to .m4a.

Why here

Why convert.now

Private
Files stay in your browser. No upload step. Nothing for anyone to see.
Fast
No queue, no upload wait. Conversion starts the moment you drop a file.
Free
No ads. No file-count limit. No sign-up wall. Just the converter.

FAQ

FLAC to M4A (AAC): common questions

No. The FLAC to M4A conversion runs entirely in your browser. Files never leave your device, and there is no server involved in the conversion at all. Open DevTools' Network tab and run a conversion if you want to confirm it — you will see the page and its code load, and no request carrying your file.

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Last updated 27 August 2026

Why convert FLAC to M4A (AAC)

FLAC vs M4A (AAC): what actually differs

How to convert FLAC to M4A (AAC)

Drop your FLAC file

Convert to M4A

Download the result

Why convert.now

FLAC to M4A (AAC): common questions

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