Convert MP3 to M4R
Your song, in the one format iPhones accept as a ringtone — converted on your own device, never uploaded.
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MP4, MOV, WebM, MKV, AVI, MP3, WAV and more — any size, no upload
🔒 Files never leave your device — everything runs in your browser.
iPhones are famously picky about ringtones: they refuse MP3s outright and accept only M4R files — which are ordinary AAC audio in an MP4 container wearing a special extension so iTunes and Finder recognize them as tones. This converter produces exactly that, entirely in your browser: drop the MP3, get a proper M4R with your file's original name, nothing sent to any server.
One honest heads-up before you convert: iOS enforces a length limit of about 40 seconds for ringtones (30 for text tones). This tool converts the whole file, so if your MP3 is a full song, trim it to the section you want first — any audio editor or even the Voice Memos app can do that. Then sync the M4R through Finder (macOS) or iTunes (Windows) into the Tones section of your device.
How it works
- Drop your file
Any common format, any size. Nothing is uploaded — the tool runs in your browser.
- Convert
Compatible files are repackaged instantly with zero quality loss; others are hardware-transcoded at high quality.
- Download
Your converted file is ready on your device — nothing to wait for, nothing to delete from a server.
Frequently asked questions
Why won't my iPhone accept an MP3 as a ringtone?
Apple only registers ringtones delivered as M4R files through iTunes, Finder, or GarageBand. M4R is technically AAC audio in an MP4 container — the same audio M4A carries — but the extension is what makes iOS treat it as a tone instead of a song.
How do I get the M4R file onto my iPhone?
Connect the phone and drag the M4R into the device's Tones section in Finder (macOS Catalina and later) or iTunes (Windows). It then appears under Settings → Sounds & Haptics → Ringtone. The file cannot be installed by AirDrop or messaging apps — Apple only accepts tones through a sync.
Is there a length limit for iPhone ringtones?
Yes — about 40 seconds for ringtones and 30 for text tones. iOS may refuse or silently skip longer files, so trim your MP3 to the part you want before converting. The converter itself does not cut anything; it converts your file exactly as given.
Does the audio quality change?
The MP3 is re-encoded to AAC, which at ringtone lengths is transparent for phone-speaker playback. The conversion happens entirely on your device — the file is never uploaded anywhere.
Is my file uploaded to a server?
No. ConvertUno runs entirely in your browser on your own device. Your file never leaves your computer or phone — there is no upload at all.
Is it really free, with no watermark?
Yes. Processing happens on your device, so serving you costs us almost nothing — no watermark, no account, no file-size limit, no daily quota.