FLAC to M4A Converter

FLAC or M4A — Which Should You Keep?

The short answer: keep the FLAC as your archive and make the M4A as a listening copy. FLAC is lossless, so it is the file you want if you might re-encode, edit, or move to a different format later. M4A is an MPEG-4 container holding AAC audio — lossy, typically five to ten times smaller, and the format Apple's Music app, iPhones, iPads and CarPlay take without complaint, where FLAC support has always been patchy.

That trade is the entire decision. If your goal is "my library plays on my iPhone", convert. If your goal is "I want a smaller lossless file", this is the wrong page — nothing here stays bit-perfect, because the Audio Codec control on this page offers AAC only, not Apple Lossless.

FLAC and M4A Side by Side

When to Keep FLAC

• You are archiving a CD rip or a purchased download and may want a different format in five years.
• You edit, master, or sample the audio — every re-encode of a lossy file compounds the damage.
• Your playback chain is a desktop, an Android phone, a network streamer, or anything running VLC or foobar2000, all of which handle FLAC natively.
• You subscribe to a lossless streaming tier and want your own files to match it. Apple Music, for example, publishes lossless up to 24-bit/48 kHz and Hi-Res Lossless up to 24-bit/192 kHz — an M4A made here is neither.

When M4A Is the Better File

• You are loading music onto an iPhone, iPad or into the Music app, where FLAC import is the awkward part of the workflow.
• Storage or bandwidth actually matters — a 40 MB FLAC track becomes roughly 4–8 MB as AAC with no audible change for most listeners on typical gear.
• You need one file that plays on both Apple and Android hardware without a third-party app. AAC-in-MP4 is about as close to universal as lossy audio gets.
• The audio is speech — podcasts, audiobooks, interviews — where 64–96 kbps mono AAC is more than enough and the FLAC is enormous for no benefit.

How to Convert FLAC to M4A

1. Upload Your FLAC File: Drag and drop your .flac files onto the page or click "+ Add Files". Queue as many as you like; they all convert with the same settings.
2. Choose Constant Bitrate, Custom Bitrate, Specific file size, or Variable Bitrate: Under File Compression, Constant Bitrate gives the most predictable result — the dropdown runs 8 kbps to 384 kbps, and 192 or 256 kbps is the usual choice for music. Custom Bitrate takes a typed value, Specific file size takes a target size and works the rate out from the duration, and Variable Bitrate offers the encoder's five AAC bands from 20k-32k up to 96k-112k. The panel opens on Quality Preset, the hands-off mode and the least predictable control here; nothing is pre-selected in it, so leaving it alone hands the decision to the server's own default rather than the rung on screen — move off it before you convert whenever you want a result you can predict.
3. Set Audio Channel, Audio Sample Rate and Trim: Leave Audio Channel and Audio Sample Rate on "ORIGINAL" to mirror the source. For spoken word, switching to MONO and 24000 HZ roughly halves the file again. Trim exports a single start time and duration.
4. Convert and Download: Click Convert and download the .m4a. Files are uploaded over an encrypted connection, converted on our servers, and deleted automatically a few hours later — no sign-up, no watermark.

Bitrate to File Size Reference

AAC at a constant bitrate is completely predictable: size is bitrate times duration, plus about 1% of MPEG-4 container overhead.

In our testing a 60-second 44.1 kHz stereo FLAC of 4,772,184 bytes encoded to 971,904 bytes at 128 kbps constant bitrate — 4.9× smaller, and within 1.2% of the arithmetic 960,000 bytes.

Frequently Asked Questions

Is M4A the same thing as MP4, and will the Music app recognise it?

They are the same container. .m4a is the audio-only naming convention Apple adopted so that music files would not open in a video player; .mp4 normally implies a video track is present. The Music app, iTunes and iOS treat .m4a as a native music file, so a converted track imports cleanly and shows its title, artist and album.

Does converting FLAC to M4A lose quality?

Yes. The M4A here holds AAC, a lossy perceptual codec — detail the encoder's psychoacoustic model judges inaudible is discarded permanently, and converting back to FLAC afterwards only rewraps what is left. At 192–256 kbps most listeners cannot pick AAC from lossless on ordinary headphones or car speakers, which is why the format dominates portable listening. Keep the FLAC if bit-perfect matters.

Can I get Apple Lossless (ALAC) out of this instead of AAC?

Not from this page. The Audio Codec control here offers AAC only, so every .m4a produced is lossy. ALAC does live inside the same MPEG-4 container and would be bit-perfect, but it is not one of the options exposed. If your goal is lossless audio that Apple software handles natively, keep the FLAC and let a lossless-capable player handle it, or convert to FLAC to AIFF for an uncompressed Apple-native file.

What bitrate should I choose for FLAC to M4A?

For music, 192–256 kbps constant bitrate is the practical sweet spot — 256 kbps buys headroom for dense or bass-heavy material, and going past 320 kbps gives very little back because AAC is efficient enough that the model has already kept what matters. For podcasts, audiobooks or voice memos, 96 kbps stereo or 64 kbps mono halves the file again with no meaningful loss. Set it under Constant Bitrate; the Quality Preset dropdown is not an alternative, because the AAC encoder here never receives it and the rung you leave showing has no bearing on the file you download.

Will my album art and tags survive?

Text tags do — title, artist and album carried in the FLAC's Vorbis comments are written into the M4A's MPEG-4 tag atoms, so your library stays organised without re-tagging. Embedded cover art does not: the audio pipeline exports the audio stream only, so a picture stored inside the FLAC is dropped. Re-adding artwork in the Music app or a tag editor after conversion takes seconds and only needs doing once per album.

Why is my M4A so much smaller than the FLAC — did something go wrong?

No, that ratio is the point. FLAC stores every sample and typically needs 500–1,100 kbps for CD-quality stereo; AAC at 192 kbps stores a perceptual model of the same audio at roughly a fifth of that. A 5–10× reduction is normal and expected. If the output is drastically smaller than that — say a few hundred kilobytes for a full song — check whether Audio Channel was left on MONO or a very low Constant Bitrate was selected.

Can I convert a whole album folder of FLAC files in one go?

Yes — queue the files together and they convert with the same settings, which is exactly what you want for an album so the whole record ends up at one bitrate. Per-track settings are not applied; if one track needs different treatment, run it separately. Track numbers and album names come from each file's own tags, so the album stays in order in your library.

How is my upload handled, and is there a size limit?

Files are uploaded over an encrypted connection, converted on our servers, and deleted automatically a few hours later — never shared, never made public, no account needed. Lossless files are large, so the real constraint is how quickly you can upload rather than anything on our side; a full album of FLAC takes a while to send even though each M4A comes back in seconds. To go the other way, M4A to FLAC rebuilds a lossless container, though it cannot restore what AAC already discarded.