Step 1: Supply your FLAC files using the button above or by haul and lay.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Get your converted AAC files.
FLAC to AAC Conversion FAQ
What does the FLAC to AAC audio converter do?
+
FLAC is lossless audio; AAC is lossy. The converter re-encodes the waveform at a configurable bitrate. The result is much smaller but discards some inaudible frequency content — usually transparent at 192 kbps+.
What bitrate should I pick for AAC?
+
320 kbps for archival quality, 256 kbps for transparent listening on most speakers, 192 kbps for streaming, 128 kbps when file size dominates. Below 96 kbps artifacts become audible on percussive content.
Is the FLAC to AAC conversion reversible?
+
You can convert the AAC back to FLAC on this site. If either format involved is lossy, the round-trip is not bit-perfect even though it is visually or audibly close.
How much smaller will the AAC be than my FLAC?
+
Typically 5-10x smaller for images, 5-15x smaller for audio. Exact ratio depends on the chosen quality level and the content — flat solid-colour images and silent audio compress far more than detailed photos or busy soundtracks.
How much quality do I lose converting FLAC to AAC?
+
Some, and it is permanent — this is the one direction where information is genuinely thrown away. FLAC holds every sample exactly; AAC discards what a psychoacoustic model predicts you will not hear. At 192 kbps and above that prediction is good enough to be transparent on most material and most equipment. Keep the FLAC as your master, because you cannot get back to it from the AAC. FLAC uses linear prediction plus Rice coding to reach roughly 50-60% of the original size while decoding back to bit-identical PCM. AAC is lossy but more efficient than MP3, and it handles up to 48 channels natively rather than being bolted onto a stereo design.
What exactly is an AAC file?
+
A bare run of encoded audio frames with no container wrapped around them. That is why two AAC files can usually be joined by simply putting one after the other, and equally why everything beyond the audio itself — a length, a seek index, cover art — has to be bolted on as a convention rather than being part of the format, so a player often has to read the whole file to work out how long it is. It is about the simplest thing that can be called an audio file, which is exactly why it turns up inside other containers more often than on its own.
Most of my FLAC files came from CDs — does that matter here?
+
Only in that the encode already happened once. A FLAC ripped from a disc was compressed at whatever bitrate the ripper was set to years ago, and that is the ceiling on everything downstream — converting cannot recover what the ripper discarded. If the discs are still on a shelf, re-ripping to a lossless format and encoding from that gives a genuinely better result than any conversion of the existing files. FLAC is the Free Lossless Audio Codec, an open format from 2001 that compresses without discarding a single sample.
Is FLAC free to use and distribute?
+
Yes, without conditions worth worrying about. The specification is public, anyone can implement an encoder or decoder without asking or paying, and nobody can change those terms later — which is why it turns up in open-source tooling, in game engines and anywhere a licence negotiation would have killed the project. Converting away from it does not undo that; the files you already have stay exactly as usable as they were.
Who defines AAC?
+
A standards body rather than a company, which is most of the reason it is everywhere. AAC was specified through the international process that produces the MPEG standards, so broadcasters, phone manufacturers, browser vendors and streaming services all implemented the same document instead of licensing somebody's product. The practical consequence is boring and useful: an AAC made by one tool decodes identically in another, and there is no vendor whose support could be withdrawn. AAC is Advanced Audio Coding, standardised in 1997 as MPEG-2 Part 7 and designed explicitly to replace MP3.
Is there a file-size limit when converting FLAC to AAC?
+
Anonymous uploads are capped at a generous default; signed-in free accounts get a higher cap, and Pro accounts have no per-file limit. Browser memory is usually the practical constraint long before our server-side limits kick in.
Can I batch-convert several FLAC files to AAC at once?
+
Yes. Drop or pick multiple FLAC files in one upload — the converter processes them in parallel and returns a ZIP of the AAC results. There is no need to repeat the upload step per file.
What happens to my FLAC files after the conversion?
+
Uploaded files and AAC outputs are auto-deleted after a short retention window. We do not inspect, share, or train on user files. Direct download links are time-limited and tied to your session.
