AAC to M4R Converter

How to Convert AAC to M4R Online

1. Upload Your .aac File: Drag and drop or click "+ Add Files" to add raw .aac files from a voice recorder app, a radio or stream capture, or audio pulled out of a video. Batch upload is supported.
2. Trim It to Ringtone Length: In Advanced Options, open Trim, enter the Start time (seconds such as 9.8, or HH:MM:SS.sss) and set Duration to 30 seconds or less. The note under Duration repeats Apple's guidance that iPhone ringtones can be up to 30 seconds long.
3. Set the AAC Bitrate (Optional): AAC is the only Audio Codec for M4R. File Compression offers a Quality Preset, Constant Bitrate (8-384 kbps), Variable Bitrate (five AAC bands, 20k-32k up to 96k-112k), Custom Bitrate in kbps, or a target file size. Audio Channel and Audio Sample Rate can stay on Original for most files.
4. Convert and Download: Click "Convert". The file is uploaded over HTTPS, processed on xconvert's servers and deleted automatically after a few hours. Download the .m4r: no sign-up, no watermark.

Why Convert AAC to M4R?

A file ending in .aac is a raw AAC bitstream, usually in ADTS framing: the encoded audio with a small header on every frame, but no MPEG-4 container around it. You find it in some phone voice-recorder apps, in internet-radio and stream captures, in the output of tools that pull the audio track out of a video without re-encoding, and in some broadcast and camera workflows.

An M4R carries the same family of codec, AAC (specifically AAC-LC), but wrapped in an MPEG-4 container with the .m4r extension. M4R is the same container and codec as M4A; the extension is what tells iOS, the Finder and iTunes that the file is a ringtone. So the job here is not a change of codec family but a change of packaging, plus the trimming every ringtone needs. xconvert writes the M4R with ffmpeg's ipod MPEG-4 muxer, the same one it uses for M4A, and ffprobe shows AAC LC in an MP4 file with major brand M4A .

Points specific to .aac sources:

• Renaming is not enough. Unlike M4A, a raw .aac file has no MPEG-4 container, so changing the extension to .m4r leaves a file that is not a valid MPEG-4 file. It has to be converted.
• HE-AAC sources. Internet radio and some streams use HE-AAC (sometimes called AAC+) at 32-64 kbps, which relies on tricks that plain AAC-LC does not use. When the output is AAC-LC, give it more bits than the source had: 96-128 kbps for music from a 48 kbps HE-AAC stream.
• One more generation. The audio is decoded and encoded again, so it is a second lossy pass. At a bitrate equal to or above the source, it is very hard to hear on a phone.

To keep the whole recording as a normal Apple audio file, AAC to M4A is the better fit. Already have an M4A instead of a raw .aac? See M4A to M4R, and to get a raw AAC stream back out of a tone, use M4R to AAC.

AAC (.aac) vs M4R: Format Comparison

AAC Profiles and What to Pick for the Ringtone

For size, use bitrate (kbps) × seconds ÷ 8: a 30-second tone is about 360 KB at 96 kbps and 480 KB at 128 kbps.

How to Set It as Your Ringtone on iPhone

Get the .m4r onto the iPhone with one of the usual routes:

• Mac (macOS Catalina or later): connect the iPhone, select it in the Finder sidebar and drag the .m4r onto it.
• Windows: connect the iPhone and add the tone in iTunes.
• iPhone only: save the .m4r to Files, import it into GarageBand on the iPhone, then use Share > Ringtone. That is Apple's documented route; the audio must not be DRM-protected, and GarageBand shortens a longer ringtone automatically on export (Apple Support).

Then open Settings > Sounds & Haptics > Ringtone and tap the tone (iPhone User Guide). For one person only: Contacts > choose the contact > Edit > Ringtone or Text Tone.

Ringtone for Android?

Android does not need M4R. Android ringtones are usually MP3 or OGG, so use AAC to MP3 for an Android tone.

Frequently Asked Questions

Isn't AAC already the iPhone ringtone format?

The codec is, the file is not. M4R is AAC inside an MPEG-4 container with a .m4r extension. A .aac file is the bare stream with no container, so iOS will not list it as a ringtone until it is converted.

Can I rename .aac to .m4r?

No. Renaming works for M4A files because M4A and M4R share the same MPEG-4 container; a raw .aac stream has no container at all. Convert it here and you get a proper MPEG-4 file with the .m4r extension.

Will converting AAC to M4R lose quality?

The audio is decoded and re-encoded as AAC-LC, which is one more lossy generation. If you choose a bitrate equal to or higher than the source, the difference is very hard to hear through a phone speaker. Choosing a much lower bitrate is what causes audible artifacts.

My .aac file came from internet radio and sounds thin after conversion. Why?

It was probably HE-AAC, which reconstructs the high frequencies with extra tools that make a low bitrate sound fuller. AAC-LC at the same low bitrate cannot do that, so raise the output bitrate to 96-128 kbps.

How long can the ringtone be?

Apple's documentation says ringtones can be up to 30 seconds long. The 40-second limit you may read about comes from the iTunes era and is not in Apple's current documentation, so keep Duration at 30 seconds or less.

Can I convert many .aac files at once?

Yes. Add them all; the same trim, bitrate, channel and sample rate settings apply to each file in the batch, and you can download them one by one or as a ZIP.

Where are my files processed?

On xconvert's servers. Files are uploaded over TLS (HTTPS) and deleted automatically after a few hours. No account is needed.