M4R ringtone converter
M4R converter
Your audio is encoded to AAC in an MP4 container and given the .m4r extension iOS uses for ringtones. iOS only lists ringtones of 40 seconds or less, so this page includes a trim control.
…or drag files and folders here. Add as many as you like — everything is processed on this device.
.aac .aif .aifc .aiff .flac .m4a .m4v .mov .mp3 .mp4 .oga .ogg .opus .qt .wav .wave
In one paragraph
Making an iPhone ringtone has two requirements and one trap. The requirements: AAC audio in an MP4 container, and the .m4r extension. The trap: iOS silently refuses to list anything longer than 40 seconds in Settings → Sounds, which is why so many “ringtone converters” produce a file that appears to work and then never shows up.
This page handles both. Set a start point and a length of up to 40 seconds, encode, and you get a file that Finder or iTunes will accept into the Tones library. The trim happens by seeking the source, so the encode covers only the section you asked for.
Does this change the audio quality?
A ringtone is heard through a small speaker for a few seconds. From an MP3 source this is a second lossy generation, and at 192 kbps it is inaudible in this context. From a WAV or FLAC source it is a first-generation encode.
- Keep the length at or under 40 seconds. Longer files encode fine but iOS will not offer them as ringtones.
- Text-tone limits are stricter still — Apple’s tooling expects around 30 seconds for those.
- Getting the .m4r onto the phone needs Finder (macOS), iTunes (Windows) or the GarageBand app. A browser cannot install a ringtone directly.
A worked example
Making a ringtone from the chorus of a song
- Drop the MP3 in and play the preview to find the moment you want.
- Set Trim start to that point and Length to 30 seconds.
- Turn on Normalise (peak, −1 dBFS) so the ringtone is loud enough to hear in a pocket.
- Convert, download the .m4r, then drag it onto your device in Finder or iTunes and pick it in Settings → Sounds.
30 seconds, starting on a strong beat, peak-normalised
30 seconds is comfortably inside the limit and longer than any ring you will actually hear. Start on a downbeat or a vocal entry rather than mid-phrase — a ringtone that starts on silence sounds broken. Peak-normalising to −1 dBFS matters more than bitrate here, because phone speakers are quiet and a ringtone mastered at −12 dBFS will be missed.
Supported formats, limits and browser notes
Sonic Batch decodes with the browser when it can (faster, no engine download) and falls back to the self-hosted WebAssembly engine when it cannot. Every combination below works in every listed browser; the column only tells you which decoder does the work.
| Input | What it is | Chrome | Firefox | Safari | iOS |
|---|---|---|---|---|---|
| MP3 | The universal lossy format. Plays on essentially every device made since 1998. | Native | Native | Native | Native |
| M4A | Apple’s default AAC container. Better quality than MP3 at the same bitrate. | Native | Native | Native | Native |
| WAV | Raw PCM samples with a small header. Perfect fidelity, roughly 10 MB per stereo minute. | Native | Native | Native | Native |
| FLAC | Lossless compression, typically 50–60% of WAV size, bit-identical when decoded. | Native | Native | Native | Native |
| AAC | Bare AAC frames with no MP4 wrapper — used by broadcast streams and some hardware. | Native | Partial | Native | Native |
| OGG | Royalty-free lossy codec. Standard in game engines, Godot, Unity and Wikimedia. | Native | Native | Engine | Engine |
| Opus | The best-sounding lossy codec below 128 kbps. Used by WhatsApp, Discord and YouTube. | Native | Native | Partial | Partial |
| AIFF | Apple’s uncompressed PCM format — the WAV equivalent for Logic and Pro Tools. | Partial | Partial | Native | Native |
| MOV | QuickTime video from iPhone and DSLR cameras. Audio is normally AAC or PCM. | Partial | Engine | Native | Native |
| MP4 | The standard video container. Its audio track is almost always AAC. | Native | Partial | Native | Native |
| Output | Encoder | Bitrates / depth | Sample rates | Tags |
|---|---|---|---|---|
| M4R | aac | 32–320 kbps | 8–48 kHz | Yes |
- Max per file
- 400.0 MB
- Max per queue
- 4.00 GB
- Max duration
- 4:00:00
- Max archive
- 1.50 GB
These are enforced ceilings, checked before any decoding starts, not measured maximums — a file over the limit is rejected rather than allowed to exhaust the tab’s memory. Real-world capacity is lower on older phones, which is why the scheduler runs one file at a time on iOS and Safari.
Where your audio goes
Nowhere. Your file is read from disk into this browser tab with the File API, decoded and encoded by code running in that same tab, and handed back to you as a download. It is never transmitted.
That is a structural property of the application, not a policy promise: there are no API routes, no server actions and no third-party processing services in this project, so there is nothing capable of receiving a file. The page’s Content-Security-Policy also restricts connections to this origin, and the automated test suite includes a browser test that fails if any network request during import, preview, conversion or download carries media bytes.
The trade-off, stated plainly:results live in your tab’s memory until you download them. Closing or reloading the page discards them. There is nothing on a server to recover, because nothing was ever put there.
Troubleshooting
The ringtone does not appear in Settings → Sounds.
Almost always the 40-second limit, or the file was copied to the Music library rather than the Tones library. Re-encode at 30 seconds and drop the .m4r onto the device’s Tones section in Finder.
iTunes says the file cannot be added.
Check the extension is exactly .m4r. Some browsers append .mp4 on download; rename it back.
The trim starts in the wrong place.
Seeking in a VBR MP3 lands on the nearest frame boundary, which can be up to 26 ms away from the exact time. Nudge the start point if a percussive hit is being clipped.
Frequently asked questions
What is an M4R file?
An MP4 file containing AAC audio, with the .m4r extension that tells iOS to treat it as a ringtone instead of a song.
Can I just rename an M4A to M4R?
Often yes, if it is already AAC in MP4 and under 40 seconds. This page does the length check and re-encoding for the cases where renaming is not enough.
How long can an iPhone ringtone be?
40 seconds is the practical limit for it to appear in the ringtone list. Text tones are usually kept to about 30 seconds.
Can I use a song I bought from the iTunes Store?
Not if it is DRM protected. Purchased tracks are encrypted and no local tool can decode them. Use a file you own outright.