File Converter

AAC to FLAC converter Free, private, no upload.

Convert AAC files to FLAC right in your browser. FLAC is lossless but much smaller than WAV, making it the standard for music archives and hi-fi players. Your files are never uploaded.

or drop files anywhere · paste with Ctrl/⌘ + V

How to convert AAC to FLAC

  1. 1 Drop your AAC files onto the page, or click “Choose files”. You can add many at once, or a whole folder.
  2. 2 FLAC is already selected as the output. Optionally open Options to adjust sample rate, channels, normalise loudness.
  3. 3 Click Convert, then Save. Converting several files? Save them all as one ZIP.

About the formats

AAC · Advanced Audio Coding

AAC is the lossy audio format used by Apple, YouTube and most streaming services. It sounds better than MP3 at the same bitrate.

FLAC · Free Lossless Audio Codec

FLAC is lossless compressed audio: about half the size of WAV with exactly the same sound. It is popular for music archives.

The conversion runs on your device using FFmpeg compiled to WebAssembly. You can adjust: sample rate, channels, normalise loudness, start at, end at.

Frequently asked questions

How do I convert AAC to FLAC?

Drop your AAC files onto the page, or click “Choose files”. You can add many at once, or a whole folder. FLAC is already selected as the output. Optionally open Options to adjust sample rate, channels, normalise loudness. Click Convert, then Save. Converting several files? Save them all as one ZIP.

Are my files uploaded to a server?

No. The conversion runs entirely in your browser using WebAssembly. Your files never leave your device, so it is safe for private photos, contracts and business data. Once the page has loaded it even works offline.

Will converting AAC to FLAC reduce quality?

No further quality is lost: FLAC stores the result losslessly. It cannot restore detail that was already discarded when the AAC file was created.

Can I convert multiple AAC files to FLAC at once?

Yes. Add as many AAC files as you like; they are converted in parallel on your device and you can download them all as a single ZIP.

Is it free? Are there limits?

It is free, with no sign-up, no watermark and no daily limits. Because nothing is uploaded there is no upload size limit either; the only limit is your device’s memory, which matters mostly for very large videos.

See everything the AAC converter and the FLAC converter can do.