How do I convert Opus to FLAC?

Add your Opus file to the upload area above, then press Convert. The FLAC file downloads straight to your device. You do not need an account, and there is no watermark.

Are my files uploaded to a server?

No. This conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can even disconnect from the internet after the page loads and it will still work.

Does converting to FLAC reduce quality?

No. FLAC is a lossless format, so the conversion preserves exactly what is in your Opus file. Note that it cannot recover detail that was already discarded when the Opus was first created — a lossless container does not undo earlier compression.

How large a file can I convert?

Up to 300 MB per file for this conversion. Because the work happens in your browser, the practical limit is your device's memory — larger files work on a desktop with plenty of RAM and may fail on an older phone.

Can I convert several files at once?

Yes. Add as many as you like and press Convert All. Each file is processed independently, so one failure does not stop the rest, and you can download everything together as a ZIP.

Can I use this on my phone?

Yes. FileTools360 works in mobile browsers on iOS and Android, including choosing files straight from your camera roll. Very large videos may run out of memory on a phone — those are better converted on a laptop.

AudioLosslessRuns in your browser

Opus to FLAC Converter

Turn Opus files into FLAC in a couple of clicks. The best low-bitrate codec available — voice and music. Lossless compression — CD quality at roughly half the size. The conversion is lossless — every pixel, sample or byte in the source is preserved.

On your deviceNever uploadedGone when you close the tabHow this works

Drop your files here

Opus files (.opus) · up to 300 MB each

or paste files from your clipboard

Ready when you are

Drop a Opus file above and FileTools360 will turn it into FLAC — right here on your device, without uploading anything.

⌘K to search converters

How to use it

1
Add your Opus files
Drag them onto the upload area, choose them from your device, or paste them from your clipboard. You can queue several at once.
2
Adjust the settings if you want to
The defaults suit most people. Open Advanced to control bitrate, sample rate and channels and start and end times.
3
Convert and download
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.

Opus and FLAC explained

Opus is the current state of the art for lossy audio, and the codec behind most voice calls you make over the internet. It performs well across an unusually wide range, from 6 kbps speech to transparent music.

FLAC compresses audio losslessly, typically to about half the size of WAV. Decompressed, it is bit-for-bit identical to the original — the compression is mathematical, not perceptual.

Where Opus files come from: Voice and video calls, modern podcast pipelines and WebRTC.
Where FLAC is used: Hi-fi music libraries and archival rips of physical media.

Opus vs FLAC

The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.

Opus compared with FLAC
Property	Source	Target
Compression	Lossy	Lossless
Introduced	2012	2001
Browser support	Modern browsers and apps; older hardware may not.	Great on desktop and Android; iOS support is newer.

Opus is stronger at: Best-in-class quality at low bitrates. Extremely low latency, which is why calls use it. Royalty-free.
FLAC is stronger at: Lossless — provably identical to the source. Roughly half the size of WAV. Rich metadata and cover art support.

Why convert Opus to FLAC?

People make this switch when they run into the limits of Opus: playback on older or embedded hardware. FLAC is the better fit when archiving music you may want to re-encode later, or storing CD rips.

Opus limitations that prompt the switch: Older hardware and car stereos generally cannot play it. Less recognised by users than MP3.
What you give up: Much larger than MP3 or AAC. Not supported natively by all portable devices.

Does converting Opus to FLAC reduce quality?

Going from Opus to FLAC moves already-compressed data into a format that stores it exactly. Nothing is lost from this point on, but nothing is recovered either — the detail Opus discarded when the file was first created is gone permanently. Expect a noticeably larger file for identical visual quality.