M4B to M4R Converter
Processing entirely on your device — large files may take a moment.
M4B is the audiobook flavour of M4A — AAC audio with chapter markers, used by Audible and Apple Books. Converting MP3 to M4R is how you turn any song into a proper iPhone ringtone that syncs via Finder or iTunes.
iLoveConverter processes everything locally on your computer, which makes it private and fast: no upload wait, no server storage, no limits. Add as many files as you like — batch conversion is built in.
How M4B compares to M4R
| M4B | M4R | |
|---|---|---|
| Compression | Lossy AAC + chapters | Lossy AAC |
| Quality | Speech-optimized bitrates | Same as M4A |
| Compatibility | Apple Books, Audible | iPhone only |
| Best for | Chaptered audiobooks | iPhone ringtones |
How to convert M4B to M4R
- 1
Select your files
Drag & drop your M4B 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 M4B format
M4B is M4A wearing an audiobook badge: the same AAC audio in an MP4 container, plus chapter markers that Apple Books and Audible apps render as a scrubbing timeline. Buy an audiobook outside Audible and it likely arrives as M4B.
The format is deliberately chained to Apple's book ecosystem. Converting M4B to MP3 sets the book free: car stereos, gym players, old iPods and every app without chapter support will play it — though the chapter marks themselves are flattened away.
+ Strengths
- ✓Chapter markers survive on Apple platforms
- ✓Efficient AAC audio
! Limitations
- −Chapters vanish in MP3 conversion
- −Non-Apple support is patchy
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 M4B to M4R?
Think of it as moving your file to the container that fits the job. Chapters vanish in MP3 conversion M4R works differently: The native iPhone ringtone format If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this M4B 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 M4B 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.
Will converting M4B to M4R reduce audio quality?
If M4R is lossless, the output contains everything the M4B 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.
Can I convert a whole folder of M4B files?
You can select many files at once and they are processed in a single batch. Output files land in one ZIP download when there is more than one result.