Is this OPUS to FLAC converter really free?

Yes. Up to 5 files at a time, no signup, no catch. The free tier adds a small watermark to image output — Pro ($9.99/mo or $49/yr) removes it, raises the file size limit to 500 MB, and unlocks unlimited batch conversion.

Are my files uploaded to a server?

No — and you can verify it yourself. Open DevTools → Network tab, then convert a file. You'll see zero upload requests. Everything runs right in your browser. We never see your files.

How long does conversion take?

Usually 1–3 seconds for a typical file. The very first conversion on a fresh page load may take 5–20 seconds while the converter engine loads — after that it's instant. Your CPU does all the work locally.

What is the file size limit?

Free: up to 10 MB per file, 5 files per batch. Pro: up to 500 MB per file, unlimited batch. If you're working with large videos or RAW photos, Pro is built for that.

Can I batch convert multiple OPUS files at once?

Yes — drop multiple files at once (or Ctrl/Cmd+click to select them) and they all convert in parallel. Free accounts handle up to 5 files per batch; Pro has no limit.

What bitrate will the converted audio use?

We default to 192 kbps for MP3, 128 kbps for OGG/Opus, and 320 kbps for M4A/AAC. These settings are perceptually transparent — most listeners can't tell the difference in a blind test.

Will my metadata (ID3 tags, album art) be preserved?

Yes, when both formats support it. Tags carry over on conversions like MP3→M4A or FLAC→MP3. WAV has limited tag support, so some metadata may not transfer.

Does converting Opus to FLAC improve audio quality?

No — the lossy Opus encoding is baked into the source. FLAC stores the decoded audio without further loss, enabling compatibility with lossless-only players, but cannot undo Opus compression.

Which hi-fi devices don't support Opus?

Many audiophile network streamers, CD transports with USB input, and older NAS music servers only support FLAC and WAV as local formats. Opus is a streaming codec and is not yet widely implemented in hi-fi hardware.

How private is this converter?

Completely private — by design, not policy. There is no upload endpoint. Files are processed right inside your browser tab and disappear the moment you close it. We collect only anonymous page-view counts; your file content is never seen or stored.

Opus to FLAC Converter — Free, Online, No Upload

How to convert OPUS to FLAC online

1
Drop your OPUS file
Drag and drop your Opus Interactive Audio Codec file onto the converter, or click to browse your files. You can select up to 5 at once. Nothing leaves your device — conversion happens right here in the browser.
2
Hit Convert — it happens locally
Click Convert and watch it go. There's no upload, no server queue, no waiting. The converter runs Opus Interactive Audio Codec → Free Lossless Audio Codec entirely in your browser tab. Most files finish in 1–3 seconds.
3
Download your FLAC
Your Free Lossless Audio Codec file is ready. Click Download, or grab a ZIP if you converted a batch. Close the tab and everything disappears — no copies kept anywhere.

OPUS vs FLAC: format overview

OPUS

Opus Interactive Audio Codec

IETF / Xiph.Org · 2012

Compression: lossy
Transparency: No

✓ Best low-bitrate quality of any audio codec
✓ Royalty-free and open standard (RFC 6716)
✗ Not supported on iOS/macOS natively

FLAC

Free Lossless Audio Codec

Josh Coalson / Xiph.Org · 2001

Compression: lossless
Transparency: No

✓ Lossless compression — identical to source
✓ 50–60% smaller than WAV with no quality loss

OPUS magic bytes: 4F 67 67 53 (Ogg container)

FLAC magic bytes: 66 4C 61 43

Why convert OPUS to FLAC?

Opus files turn up in some specific and increasingly common places: Discord voice messages, WhatsApp voice notes, Telegram audio, WebRTC recordings, and browser-captured audio all use Opus as their codec. When those recordings need to be edited in professional audio software, archived long-term, or played back on hi-fi hardware, Opus creates an immediate problem — most professional DAWs, audiophile music players, and high-end hardware simply don't recognise it.

FLAC is the format that professional and audiophile software understands. Audacity, Reaper, iZotope RX, and most broadcast audio editors can open FLAC without any additional plugins. Roon, Audirvana, foobar2000, and essentially all hi-fi network streamers treat FLAC as a primary format. Converting Opus to FLAC stores the decoded Opus audio in a FLAC container without any further encoding — the audio is decoded once and written to FLAC, with no additional quality loss from that point forward.

The honest limitation is that the FLAC output won't sound better than the Opus source. Opus is a lossy codec, and the compression it applied when the audio was originally encoded can't be undone. What you gain from the FLAC conversion is editability, archivability, and compatibility with hardware and software that refuses Opus input. For anyone processing Discord voice messages or WebRTC recordings in a DAW, this conversion is the essential first step.

Quality & file size: OPUS to FLAC

Typical file sizes: OPUS 1–3 MB → FLAC 20–40 MB.

Converting from lossy OPUS to lossless FLAC will not recover detail the OPUS codec already discarded — but the output will not degrade any further. This is useful when you need a lossless format for editing or compatibility without additional compression artifacts.

Color depth: OPUS supports standard color, FLAC supports standard color.

Transparency: OPUS does not support transparency. FLAC does not support transparency — transparent areas become solid white.

Frequently asked questions

Privacy: how FormatDrop handles your files

Your OPUSfiles are converted 100% inside your browser. They are never uploaded to our servers, never stored, and never seen by anyone other than you. This isn't a privacy policy claim — it's an architectural guarantee: our server has no endpoint that receives file bytes.