Add your OPUS file
Drop one or more .opus files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
OPUS to M4R
Re-encoding .opus audio as .m4r changes how the sound is compressed and which players will accept it. Free, private, and validated — the file never leaves your browser.
100% private for supported formats
Runs on your deviceConvert supported files
Drop OPUS files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting Opus audio to Apple ringtone
Re-encoding .opus audio as .m4r changes how the sound is compressed and which players will accept it. An .opus file contains audio compressed with the Opus codec, stored in an Ogg container. Opus represents the current state of the art in lossy audio, beating MP3, AAC, and Vorbis in listening tests at nearly every bitrate from whisper-thin speech settings up to transparent music encoding.
An .m4r file is an iPhone ringtone: AAC audio in an MPEG-4 container, identical to an .m4a in everything but the extension. Apple uses .m4r purely as a routing marker so iTunes and iOS file the audio under Tones instead of Music. For this route the practical draw is the only ringtone format iOS accepts and full AAC quality, indistinguishable from the source track — balanced against tones over 40 seconds are rejected outright, which is worth knowing before you commit a large batch.
Why convert OPUS to M4R?
The practical trigger for this conversion is usually a mismatch: with .opus, older car stereos, AV receivers, and MP3 players have never heard of it. Switching to .m4r buys you the only ringtone format iOS accepts, which is why it is the better fit for turning a favorite song's hook into a custom iPhone ringtone. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
OPUS vs M4R at a glance
| Aspect | Opus audio (.opus) | Apple ringtone (.m4r) |
|---|---|---|
| Format type | Lossy — discards detail it judges invisible to shrink files | Lossy — discards detail it judges invisible to shrink files |
| How it stores data | the hybrid SILK/CELT design switches coding modes automatically based on content | shares the ISO base media layout of .m4a, carrying AAC-LC audio |
| Strongest at | compressing podcast and voice-chat audio to tiny files | turning a favorite song's hook into a custom iPhone ringtone |
| Weak spot | older car stereos, AV receivers, and MP3 players have never heard of it | tones over 40 seconds are rejected outright |
| Metadata | vorbis comments in the OpusTags header, including cover art via METADATA_BLOCK_PICTURE, plus an output-gain field used for loudness normalization | standard iTunes atoms apply, though iOS shows only the title in the ringtone picker |
Pick M4R as the output
Select .m4r in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if M4R is selectable, the route is real and validated.
Convert on your device
Press Convert. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid M4R file. Outputs keep the original filename with the .m4r extension.
OPUS to M4R questions, answered
Will converting OPUS to M4R lose quality?
A second lossy step always costs a little, because opus is lossy-oriented and m4r is lossy-oriented and each encoder discards detail differently (generation loss). At the default quality the difference is rarely visible; avoid repeated round-trips between .opus and .m4r.
Is it private to convert OPUS files here?
Yes — the .opus file is processed inside your browser tab and never uploaded. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device. Close the tab and the file is gone from memory.
Where will the M4R file work?
iPhones accept .m4r only through iTunes or Finder sync and GarageBand export, and every Apple device can play it since the audio is ordinary AAC. Other platforms open the file happily after a rename, though Android sources its ringtones from plain MP3 or OGG instead.
Will the M4R file be bigger or smaller than my OPUS?
It depends on the content: shares the ISO base media layout of .m4a, carrying AAC-LC audio. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my OPUS file?
This converter strips container metadata deliberately (the FFmpeg command runs with metadata mapping disabled) so exported files do not leak recording details. In the source, vorbis comments in the OpusTags header, including cover art via METADATA_BLOCK_PICTURE, plus an output-gain field used for loudness normalization; none of it is transmitted anywhere because the file never leaves your browser.
Can I convert M4R back to OPUS?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .opus → .m4r → .opus is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.