Upload a MP3 file and get a FLAC back. No signup, no watermark, no limit on how many.
MP3 is the format that made portable music work, and thirty years on it is still the one every device, car stereo, DAW and browser will open without being asked twice.
Where you run into it: Downloads, podcast feeds, old music libraries, anything a client sends you and expects you to just play.
What it costs you: It throws audio away to get small, and at 320 kbps almost nobody can hear what went. What matters is that the discarded part never comes back.
FLAC compresses losslessly: it typically halves a WAV and gives back bit-for-bit the same audio when decoded. It is free, open, and widely supported outside Apple's world.
Where you run into it: Archived rips, Bandcamp and Qobuz downloads, anyone who keeps a music library they intend to still have in ten years.
What it costs you: Half of enormous is still large, and some hardware — car head units especially — will not touch it.
The MP3 is decoded and those samples are compressed again, this time without discarding anything — so the FLAC is a perfect record of an imperfect file. That is worth stating plainly, because it is the most common misunderstanding in audio: this conversion cannot improve an MP3. What it genuinely does is produce a much larger file that carries a checksum of its own contents and a tag system everything reads. An MP3 decodes to 16 bits, which is what FLAC writes here, so the encoding step itself costs nothing.
The honest reasons all concern what will accept the file, never how it sounds. Some upload paths insist on lossless — certain distribution and mastering services, some archive submissions, DJ libraries configured for FLAC or WAV only — and if that is your situation, go ahead. If the aim is a music library, do not: a FLAC made from an MP3 is what collectors call a transcode, the spectrogram gives it away, and it costs six times the disk for audio exactly as good as the MP3 you already had. Artist, title and album do come across, so at least nothing needs retyping.
Yes, entirely, and there is no cap on how many files you convert. No account, no watermark, no trial.
No further loss and no recovery — and on this pair the evidence is visible rather than theoretical. Open the result in any spectrogram viewer and the MP3's ceiling is still there: at 128 kbps there is effectively nothing above 17 kHz, while a 320 kbps source reaches much higher. That empty band at the top is the signature of a lossy origin, and it is how anyone can tell a FLAC was made from an MP3 rather than from a disc.
Five to eight times the MP3, because FLAC has nothing to exploit: it stores every decoded sample and has no way of knowing that some were reconstructed from a lossy file. A 5 MB album track lands somewhere around 30 MB. The one mercy is that FLAC is still about half of a WAV, so of the two ways to make this particular mistake, it is the cheaper one.
Yes — FLAC is one of the formats this converter writes, so the reverse page exists at /flac-to-mp3/. The trip out is exact, because FLAC discards nothing — it is the return to MP3 that re-encodes. A round trip therefore costs one more generation rather than two, and the FLAC in the middle was never an improvement on the MP3 you started with.
The file is uploaded to do the conversion — nothing here runs in your browser — and both your upload and the converted result are deleted the moment the file is sent back. Nothing is stored and nothing is logged beyond the request itself.