Convert MP3 to FLAC

No, and it is worth being blunt: nothing can. The MP3 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. MP3 is technically outclassed by AAC and Opus at every bitrate, cannot store more than two channels usefully, and always adds a small encoder delay.

Often not. MP3 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 MP3. FLAC is still several times larger than a good lossy file, and Apple’s ecosystem only added support recently and grudgingly.

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).

If MP3 is lossy and FLAC is lossless (e.g. MP3 → WAV), the FLAC file is no better than the MP3 — you can't recover information that's already been thrown away. If MP3 is lossless and FLAC is lossy, expect the FLAC codec to recompress; at 192 kbps this is transparent for most content.

Yes — title, artist, album, year, track number, album art, and chapter markers (important for audiobooks) are read from MP3 and written into the FLAC container where the FLAC format supports tags. M4B audiobook structure round-trips into M4B and AAX → M4B output.

Yes — drop a folder of MP3 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.

By default yes (48 kHz MP3 → 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.

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.

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.

Yes — uploaded MP3 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.

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.