AAC to M4R
Turn an AAC audio file into an iPhone M4R ringtone — optional 40-second trim, no quality loss. Runs entirely in your browser; nothing is uploaded.
Input
Lossless: the AAC audio is copied into a new M4R container without re-encoding, so quality is identical.
M4R audio
Upload an AAC file and press Convert to M4R. Everything runs in your browser — the file is never uploaded.
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Guides
What AAC to M4R does
iPhone ringtones are AAC audio in an MP4 container with the .m4r extension. If you have a plain .aac file, this tool repackages it as M4R without re-encoding, so the ringtone sounds exactly like the source.
How to use it
- Upload an AAC file.
- Keep the 40-second limit on and choose where the clip should start (iPhone ringtones can be at most 40 seconds), or switch it off to keep the whole file.
- Click Convert to M4R, preview, and download.
Installing the ringtone
On a Mac, connect the iPhone and drag the .m4r file onto it in Finder. On Windows, use the Apple Devices app or iTunes. Then pick it under Settings → Sounds & Haptics → Ringtone.
Good to know
The tool expects raw AAC in ADTS format, which is what a plain .aac file is. Trims snap to whole audio frames (about 23 ms), so the cut point can be off by that much.
Privacy
The file is processed on your device. Nothing is sent to a server.