OPUS to M4R Converter
Processing entirely on your device — large files may take a moment.
Opus Audio and iPhone Ringtone exist for different jobs: Opus is today’s most efficient voice/music codec — WhatsApp, Telegram, Discord and YouTube all use it. Converting MP3 to M4R is how you turn any song into a proper iPhone ringtone that syncs via Finder or iTunes.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How OPUS compares to M4R
| OPUS | M4R | |
|---|---|---|
| Compression | Lossy (6–510 kbps) | Lossy AAC |
| Quality | State of the art | Same as M4A |
| Compatibility | Software strong, hardware lagging | iPhone only |
| Best for | Calls, live streams, chat | iPhone ringtones |
How to convert OPUS to M4R
- 1
Select your files
Drag & drop your OPUS files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to M4R". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted M4R file individually, or grab everything at once as a ZIP archive.
About the OPUS format
Opus (IETF RFC 6716, 2012) is the codec that ended the argument: it merges Skype's CELT and Xiph's SILK into one royalty-free format that is simultaneously the best low-latency speech codec and a superb music codec. WebRTC calls, Discord, WhatsApp, WhatsApp calls, YouTube's low-bitrate streams and Zoom all run on it.
At 6 kbps it keeps speech intelligible; at 128 kbps it is transparent for music; latency can dip below 5 ms for live conversation. Its weakness is hardware: dedicated chips and some car/hi-fi devices still lack it, and standalone .opus files are less recognized than MP3 on random devices.
+ Strengths
- ✓Best quality-per-bit across speech and music
- ✓Ultra-low latency — built for live calls
- ✓Royalty-free IETF standard
! Limitations
- −Hardware support still incomplete
- −Not a mastering or archival format
About the M4R format
M4R is simply iPhone ringtone packaging: an AAC audio file (same as M4A) capped at 40 seconds, named .m4r so iOS treats it as a ringtone instead of a song. GarageBand and Finder sync are the supported paths to install one; the audio itself is ordinary AAC.
Practical workflow: pick the 30–40 second chorus you want, convert to M4R, sync it to the phone, and set it in Sounds & Haptics. Nothing about the audio changes — the extension and the length limit are the entire format.
+ Strengths
- ✓The native iPhone ringtone format
- ✓Simple — it is AAC with a new name
! Limitations
- −Hard 40-second length cap
- −Installation requires sync or GarageBand
Why convert OPUS to M4R?
There is a concrete reason this conversion exists: Hardware support still incomplete M4R sidesteps that — The native iPhone ringtone format If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this OPUS to M4R converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for OPUS to M4R?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Are tags like title and artist preserved?
Tag handling varies between target formats and this conversion focuses on the audio itself. For archival copies where tags matter, keep the original file; the converted copy is for playback and sharing.
Will converting OPUS to M4R reduce audio quality?
If M4R is lossless, the output contains everything the OPUS file contains — no further loss is added. If M4R is lossy, one recompression pass is unavoidable; the quality slider controls how much. Loss that already happened in the source file can never be undone by converting.