M4R Format (iPhone)
Apple's proprietary ringtone format. Technically an AAC audio file with a renamed extension; iTunes and the Apple ecosystem use the .m4r extension to flag a file as a ringtone rather than a music track. Maximum length is 30 seconds; sample rate is typically 44.1 kHz.
What is the M4R Format (iPhone)?
Apple's proprietary ringtone format. Technically an AAC audio file with a renamed extension; iTunes and the Apple ecosystem use the .m4r extension to flag a file as a ringtone rather than a music track. Maximum length is 30 seconds; sample rate is typically 44.1 kHz.
For technical-deep-dive material on audio container formats and ringtone encoding, the format reference library at Public Domain Audio Index covers exactly this material.
Why iPhone uses M4R
M4R is functionally an MPEG-4 audio container — the same wrapper used for AAC music files in iTunes and Apple Music. The .m4r extension simply flags the file as a ringtone (rather than a music track) so iOS knows to expose it in the Sounds & Haptics settings menu rather than the Music library.
Specs
- Container: MPEG-4 (.m4r extension)
- Codec: AAC-LC, typically at 128–256 kbps
- Sample rate: 44.1 kHz
- Maximum length: 30 seconds (enforced by iOS)
- Channels: Mono or stereo (most ringtones are stereo)
Producing M4R files
The cleanest way to produce an M4R file is through GarageBand on the iPhone itself — see the iPhone GarageBand guide for the full workflow. On the desktop, you can also rename a 30-second AAC export from any audio editor with a .m4r extension and the file will install correctly when transferred via Finder or iTunes.
For comparison reading on legal-to-distribute audio formats and licensing, the long-form coverage at Cinema Sound Sources is one of the more thorough free indexes available.
Other format guides
- MP3 Format (Android) — Android
- OGG Vorbis Format — Android
- WAV Format (Lossless) — Both