MP3 to M4R converter
MP3 to M4R is the classic iPhone ringtone conversion: the MP3 is decoded, trimmed to 40 seconds or less, re-encoded as AAC and saved in an MPEG-4 container with the .m4r extension.
Drop an audio or video file here
MP3, M4A, WAV, OGG, FLAC, MP4, MOV… — processed on your device, never uploaded
How to convert MP3 to M4R
- Open the MP3 file. Click Open file or drop it on the editor. It is decoded locally.
- Choose what to keep. The loudest 30 seconds are selected automatically — drag to change it.
- Check the settings. Format is set to M4R at 192 kbps. Add fades or Normalize if you like.
- Download. Click Download M4R.
About MP3 to M4R conversion
Renaming an .mp3 to .m4r does not work — the iPhone expects AAC audio inside an MPEG-4 file. This converter does the real conversion in your browser using the built-in AAC encoder, then writes the M4R container itself, including a title tag.
The page selects the loudest 30 seconds of the MP3 automatically. Drag the selection to choose a different part, then download and drag the M4R onto your iPhone in Finder (Mac) or iTunes (Windows). On iOS 26 you can skip the computer: choose M4A, keep it under 30 seconds, and use Files → Share → Use as Ringtone.
FAQ
Can I just rename MP3 to M4R?
No. An M4R must contain AAC audio in an MPEG-4 container. Renaming leaves MP3 data inside, which Finder and iTunes reject.
How long can the M4R be?
Up to 40 seconds for a ringtone synced from a computer.
Are my files uploaded?
No. Audio is decoded, edited and encoded in your browser with the Web Audio API, WebCodecs and a JavaScript MP3 encoder. Nothing is sent to a server, so it also works on slow connections once the page has loaded.
Which formats can I open?
Anything your browser can decode: MP3, WAV, M4A/AAC, OGG Vorbis, Opus and FLAC, plus the audio track of MP4, MOV and WebM videos. Chrome and Edge support the widest range.