Add your M4A file
Drop one or more .m4a 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.
M4A to M4R
Re-encoding .m4a 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.
Private for supported formats, processed in your browser
Runs on your deviceConvert supported files
Drop M4A 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 MPEG-4 audio to Apple ringtone
Re-encoding .m4a audio as .m4r changes how the sound is compressed and which players will accept it. An .m4a file is an MPEG-4 container that holds only audio, most often AAC and occasionally Apple Lossless. Apple coined the .m4a extension so audio would not be confused with .mp4 video, and it remains the default for iTunes purchases, Apple Music downloads, and Voice Memos.
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 M4A to M4R?
The practical trigger for this conversion is usually a mismatch: with .m4a, the extension hides whether the contents are lossy or lossless, muddying quality expectations. 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.
M4A vs M4R at a glance
| Aspect | MPEG-4 audio (.m4a) | 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 | an ISO base media container restricted to audio tracks, structurally a sibling of MP4 | shares the ISO base media layout of .m4a, carrying AAC-LC audio |
| Strongest at | managing music inside iTunes and Apple Music libraries | turning a favorite song's hook into a custom iPhone ringtone |
| Weak spot | the extension hides whether the contents are lossy or lossless, muddying quality expectations | tones over 40 seconds are rejected outright |
| Metadata | iTunes-style metadata atoms: title, album, artwork, composer, BPM, and the iTunSMPB gapless-playback data. A file converted here has an empty atom set, because metadata mapping is disabled on every route: title, album, artwork, composer and BPM are dropped, and no iTunSMPB is written, so gapless playback information does not survive | standard iTunes atoms apply, though iOS shows only the title in the ringtone picker. A file converted here carries no atoms at all, because metadata mapping is disabled on every route, so not even that one title is written and it has to be set afterwards in a tag editor |
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 checked before the download unlocks: where M4R has a signature or a structure this converter can read back, the file is re-opened and parsed, and where it has neither, the check is that a non-empty file of the declared type came back. A result that fails is reported as an error instead of being offered for download, and outputs keep the original filename with the .m4r extension.
M4A to M4R questions, answered
Will converting M4A to M4R lose quality?
A second lossy step always costs a little, because m4a 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 .m4a and .m4r.
Is it private to convert M4A files here?
Yes. The .m4a 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. Novus Convert writes .m4r with exactly the same command as the .m4a target, AAC at 55 to 192 kbps into the MPEG-4 muxer with a fast-start atom layout; the extension on the download is the only difference. Two things it does not do, and which the 40-second ceiling above makes important: it never trims or shortens the audio, and it writes no ringtone metadata, so converting a four-minute song produces a four-minute .m4r that iOS will reject. Trim first, then convert, then sync through Finder or iTunes. Input is capped at 500 MB.
Will the M4R file be bigger or smaller than my M4A?
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 M4A 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, iTunes-style metadata atoms: title, album, artwork, composer, BPM, and the iTunSMPB gapless-playback data. A file converted here has an empty atom set, because metadata mapping is disabled on every route: title, album, artwork, composer and BPM are dropped, and no iTunSMPB is written, so gapless playback information does not survive; none of it is transmitted anywhere because the file never leaves your browser.
Can I convert M4R back to M4A?
Yes. The reverse route exists as a separate tool. Bear in mind that round-tripping .m4a → .m4r → .m4a is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.