Upload a Opus file and get a FLAC back. No signup, no watermark, no limit on how many.
Opus is the best lossy codec in general use: at 64 kbps it beats formats running at twice that, which is why real-time applications standardised on it.
Where you run into it: WhatsApp and Telegram voice notes, Discord, Signal, Zoom, and most browser-based calls.
What it costs you: Everything can play it inside an app and remarkably little can play it as a file — a voice note saved to a desktop is the classic case, and the usual reason to convert one.
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.
Worth being clear about: converting Opus to FLAC does not restore anything. What Opus threw away is gone, and wrapping the result in a lossless format simply preserves the damaged version perfectly. The file will get several times larger for no gain in sound. Do it when a tool or a workflow demands FLAC input — many editors and DAWs do — and not in the hope of better audio.
Yes, entirely, and there is no cap on how many files you convert. No account, no watermark, no trial.
It does not lose anything further, but it does not recover anything either. FLAC will store your Opus audio perfectly, damage and all. Converting this way for sound quality is the single most common misunderstanding about audio formats.
Considerably larger — usually five to ten times the Opus. A lossless format stores every sample, and it has no way of knowing that some of them were reconstructed from a lossy file.
Not here. Opus can be read but not written by this converter — ffmpeg decodes it happily, and encoding back to it would mean a format almost nothing plays. If you need the original Opus, keep it rather than recreating it.
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.