Convert AAC to FLAC Online Free
Convert AAC audio to FLAC lossless format. FLAC provides lossless compression that preserves all audio data for editing, archiving, and compatibility with FLAC-native players and systems.
ChangeThisFile converts your AAC to FLAC using FFmpeg on secure servers. FLAC is a lossless format widely supported by audiophile players, NAS audio servers, and Linux systems. Note that converting from lossy AAC to lossless FLAC preserves AAC quality but cannot recover data lost during original AAC encoding. Files are auto-deleted after conversion, free with no signup.
Convert AAC to FLAC
Drop your AAC file here to convert it instantly
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AAC vs FLAC: Format Comparison
Key differences between the two formats
| Feature | AAC | FLAC |
|---|---|---|
| Compression Type | Lossy | Lossless |
| File Size (3 min) | ~3–6 MB | ~20–40 MB |
| Audio Data Preserved | Lossy (some data discarded) | All data preserved |
| Apple Device Support | Native | Requires third-party app |
| Linux / audiophile support | Limited | Excellent |
| Streaming Platform Use | Dominant | Tidal, Deezer HiFi |
| Re-encoding Loss | Yes (each encode) | No (lossless re-encode) |
| Open Standard | Partially | Yes (royalty-free) |
When to Convert
Common scenarios where this conversion is useful
Archiving AAC tracks in a lossless container
Convert AAC files to FLAC to store them in a lossless container. While the audio quality is limited by the original AAC encoding, FLAC prevents further generation loss during future re-encoding.
Audiophile media players and NAS systems
Audiophile-grade players (Foobar2000, Roon, Plex) and NAS-based audio servers (Naim, Bluesound, Logitech Media Server) natively support FLAC. Convert AAC libraries to FLAC for these environments.
Android and Linux music players
Many Android and Linux music players have excellent FLAC support but limited AAC support. Convert AAC files to FLAC for seamless playback on these platforms.
Preventing further quality loss in editing
When editing audio that will be re-exported, working with a FLAC intermediate prevents additional lossy re-encoding. Convert your AAC source to FLAC before editing, then export from FLAC.
How to Convert AAC to FLAC
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1
Upload your AAC file
Click the upload area or drag and drop your AAC or .m4a file. Files up to 50MB are accepted. The upload uses HTTPS encryption for security.
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2
Convert to FLAC
Click Convert. FFmpeg decodes the lossy AAC audio to PCM and then losslessly compresses it as FLAC. The resulting FLAC reflects the quality of the original AAC encoding.
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3
Download your FLAC file
Download the FLAC file when conversion is complete. It will be larger than the source AAC. The file is automatically deleted from our servers after download.
Frequently Asked Questions
No. Converting from lossy AAC to lossless FLAC does not recover any audio data that was discarded during AAC encoding. The FLAC output is lossless, but the quality ceiling is set by the original AAC encoding.
FLAC prevents further quality loss. Once in FLAC, you can edit, re-encode, and transcode without additional generation loss from compression artifacts. It is also more compatible with audiophile and Linux-based audio systems.
Yes, significantly. AAC uses lossy compression to achieve small file sizes. FLAC stores compressed lossless audio, which is much larger. A 5 MB AAC file might become 25-35 MB as FLAC.
FLAC uses Vorbis comment tags, while AAC typically uses iTunes-style MP4 metadata. Most metadata fields (title, artist, album, track number) will transfer, but some iTunes-specific fields may not map perfectly.
Not natively. The default Music app on iPhone and iPad does not support FLAC. You need a third-party player like VLC for iOS or Doppler to play FLAC files on Apple devices.
Yes. Foobar2000 has excellent native FLAC support. The converted FLAC file will play perfectly in Foobar2000 along with all metadata. Foobar2000 also supports ReplayGain scanning of FLAC files.
Yes. Starting from a FLAC file for subsequent conversions means only one generation of lossy encoding loss. Re-encoding from a lossy source like AAC adds additional loss each time.
Yes. Your file is uploaded over HTTPS, processed by FFmpeg on our secure server, and automatically deleted after download. We do not store or analyze your audio files.
FFmpeg preserves the sample rate from the AAC source (typically 44100 Hz or 48000 Hz). The FLAC output is at 16-bit depth, standard for CD-quality audio.
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