Step 1: Drop your AAC files using the button above or by deposit and leave.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Receive your converted FLAC files.
AAC to FLAC Conversion FAQ
How do I convert AAC audio to FLAC without quality loss?
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Upload the AAC file and our converter chooses the FLAC codec / bitrate combination that matches the source. Lossless target (FLAC = WAV / FLAC / ALAC) preserves every sample; lossy target (FLAC = MP3 / AAC / OGG) defaults to 192 kbps which is transparent for spoken-word audiobooks and most music.
Does converting AAC to FLAC improve the audio quality?
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No, and it is worth being blunt: nothing can. The AAC already discarded detail during its original encode, and wrapping what remains in a lossless FLAC preserves exactly that — no more. The file gets several times larger and sounds identical. It is still the right move before editing, because FLAC will not add a second generation of artefacts when you export. FLAC gives you WAV fidelity at half the size, with proper metadata tags and embedded artwork, which is why it dominates lossless music libraries. AAC is patent-encumbered, and a handful of very old players still refuse it where they would accept an MP3.
Will the FLAC play in my car or on older hardware?
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Often not. AAC is decoded by essentially everything, including car head units and elderly players; FLAC needs software that knows the codec, which standalone hardware frequently does not have. If the destination is a car stereo or a portable player, that is a strong argument for staying on AAC. FLAC is still several times larger than a good lossy file, and Apple’s ecosystem only added support recently and grudgingly.
What bitrate does the FLAC file use?
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Default is 192 kbps for lossy FLAC; pass-through for lossless FLAC. Override to 320 kbps for audiophile or 64-96 kbps for spoken-word audiobooks (transparent for voice, halves the file size).
Will going from AAC to FLAC reduce my audio quality?
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If AAC is lossy and FLAC is lossless (e.g. MP3 → WAV), the FLAC file is no better than the AAC — you can't recover information that's already been thrown away. If AAC is lossless and FLAC is lossy, expect the FLAC codec to recompress; at 192 kbps this is transparent for most content.
Does the AAC to FLAC converter keep ID3 / metadata tags?
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Yes — title, artist, album, year, track number, album art, and chapter markers (important for audiobooks) are read from AAC and written into the FLAC container where the FLAC format supports tags. M4B audiobook structure round-trips into M4B and AAX → M4B output.
Can I batch convert hundreds of AAC files to FLAC?
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Yes — drop a folder of AAC files in and we process them in parallel. Premium has more parallel workers and no per-file size cap, so a 500-file batch finishes in minutes rather than tens of minutes.
Will the FLAC keep the same sample rate as AAC?
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By default yes (48 kHz AAC → 48 kHz FLAC). If you need to downsample for compatibility (e.g. 96 kHz → 44.1 kHz for CD burning) the advanced sample-rate option does this with high-quality resampling.
Can I normalize loudness in the AAC to FLAC step?
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Yes — the loudness-normalize option applies ITU-R BS.1770 / EBU R128 normalization to the FLAC output, targeting -14 LUFS (streaming standard), -16 LUFS (podcast standard), or -23 LUFS (audiobook standard). Useful when batch-converting tracks with varying mastering levels.
Will the FLAC play on my car stereo / iPod / audiobook app?
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MP3 plays universally. AAC plays on Apple, most Android, Sonos. FLAC plays on Sonos and Android, less well on older iPods. M4B audiobooks play with chapter navigation on iOS Books, Audiobookshelf, and Smart Audiobook Player. The advanced options include device presets.
Is my AAC file private during conversion?
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Yes — uploaded AAC files are processed in isolated workers and deleted within minutes. We never play, store, or share the audio content. Especially important when working with personal audiobook libraries.
How long does converting a 10-hour audiobook AAC to FLAC take?
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Same-codec re-mux: 10-30 seconds. Re-encode to a different codec: typically 10-20% of source duration, so a 10-hour audiobook finishes in 60-120 minutes. Chapter markers survive the round-trip and split cleanly.
