MP3 → 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 192 kbps for lossy FLAC; pass-through for lossless FLAC. Override to 320 kbps if you want maximum lossy fidelity, 128 kbps for size-constrained podcast distribution, or 96 kbps for voice-only sources where the smaller file matters more than studio detail.

If MP3 is lossy (MP3, AAC) and FLAC is lossless (WAV, FLAC), the FLAC is no better than the MP3 — you cannot recover information already discarded by the lossy MP3 codec. If MP3 is lossless and FLAC is lossy, expect the FLAC encoder to recompress; at 192 kbps the loss is imperceptible to most ears.

Yes — title, artist, album, year, track number, album art, BPM, replay-gain are read from the MP3 container and written into the equivalent fields on the FLAC container. ID3v2 (MP3), Vorbis comments (OGG, FLAC), MP4 atoms (AAC, M4A), RIFF INFO (WAV), iXML chunks all map cleanly. FLAC is the Free Lossless Audio Codec, an open format from 2001 that compresses without discarding a single sample.

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. Folder structure is preserved in the output ZIP.

By default yes (a 48 kHz MP3 produces 48 kHz FLAC, a 44.1 kHz MP3 produces 44.1 kHz FLAC). For specific compatibility — e.g. downsampling 96 kHz studio masters to 44.1 kHz FLAC for CD burning, or upsampling 22 kHz voicemail to 44.1 kHz FLAC — the sample-rate dropdown applies high-quality SOX-style resampling.

Yes — the loudness-normalize option applies ITU-R BS.1770 / EBU R128 normalization to the FLAC output, targeting -14 LUFS (streaming standard) or -16 LUFS (podcast standard) or a custom value. Useful when batch-converting tracks with varying mastering levels into a single FLAC playlist.

MP3 plays universally on every device made in the last 20 years. AAC plays on Apple, most Android, Sonos, and modern car stereos. FLAC plays on Sonos and recent Android, less well on older iPods. WAV plays on everything but the file is huge. The device-target dropdown picks a safe FLAC codec for the platform you specify.

Yes — uploaded MP3 files are processed in isolated workers and deleted within minutes. We never play, store, or share the audio content. The pipeline runs on hardware we control end-to-end; no third-party services receive your file.

Same-codec re-mux (e.g. AAC inside M4A -> AAC inside MP4): 10-30 seconds. Codec change (e.g. FLAC -> MP3 or WAV -> AAC): typically 10-20% of source duration, so a 1-hour MP3 -> FLAC finishes in 6-12 minutes on the standard pipeline.