Free online FLAC to M4R converter

iPhones do not accept FLAC directly as a custom ringtone, so a lossless music file must be converted before it can be imported as a tone. M4R is the Apple-oriented ringtone filename used for this purpose, typically containing AAC audio in an MPEG-4 container.

What FLAC is

FLAC, or Free Lossless Audio Codec, compresses audio without discarding source information; decoding it reproduces the original PCM audio. It is common for CD rips, music archives, editing sources, high-resolution downloads, and Linux audio workflows. FLAC preserves more information than lossy formats such as AAC or MP3, but its larger files and limited iPhone support make it unsuitable as a directly imported ringtone.

What M4R is

M4R is Apple’s ringtone filename extension. In practice, an M4R file is normally an MPEG-4 audio container with AAC audio, similar to an M4A file whose extension identifies it for ringtone use. AAC produces much smaller files than FLAC while providing sufficient quality for phone playback. M4R is intended for short iPhone tones, not for preserving an original music master.

Convert the file with 101convert.com

You can convert the file on 101convert.com for free without installing software:

1. Open the converter and upload the FLAC file.
2. Select M4R as the output format.
3. Start the conversion and download the resulting .m4r file.
4. If the service provides trimming or start-time controls, select the desired clip before converting.

Use a desktop tool instead for private recordings, large files, repeated conversions, or exact control over trimming and encoding.

Convert with FFmpeg

FFmpeg runs on Windows, macOS, and Linux and is suitable for batch processing. Open a terminal in the folder containing the FLAC file, then encode a 30-second clip with:

ffmpeg -i "input.flac" -t 30 -c:a aac -b:a 256k -vn "ringtone.m4r"

To begin at a specific point and encode the following 30 seconds, use:

ffmpeg -ss 00:01:15 -i "input.flac" -t 30 -c:a aac -b:a 256k -vn "ringtone.m4r"

Replace the input and output filenames as needed. The -ss option selects the starting position, -t 30 limits duration, -c:a aac selects AAC encoding, -b:a 256k sets the bitrate, and -vn excludes video. FFmpeg’s output is an MPEG-4 audio file with an M4R extension; changing an M4A filename to M4R alone is not conversion and does not change the audio codec.

To retain the entire source, omit -t 30, but an iPhone may reject or fail to offer a ringtone that exceeds its supported duration. The usual iPhone custom-ringtone limit is 30 seconds.

Transfer the M4R to an iPhone

1. Connect the iPhone to the computer and unlock it.
2. On macOS, open Finder, select the iPhone in the sidebar, and drag the M4R file into the device’s general or tones area when available.
3. On Windows, use the current Apple device-management application or iTunes where it is still installed, and add or drag the M4R file through the device’s ringtone or tones workflow.
4. On the iPhone, open Settings → Sounds & Haptics → Ringtone and select the imported tone.

Apple Music is primarily a music library application and is not the general replacement for Finder or iTunes ringtone transfer. The exact import controls vary by operating-system version; if the file is not listed, verify its encoding, extension, and duration.

Quality and compatibility limits

FLAC-to-M4R conversion is lossy: the FLAC is decoded and then re-encoded as AAC. Keep the original FLAC as the archival copy because AAC cannot restore information removed during encoding. A bitrate of 192–256 kbps AAC is suitable for a short ringtone; increasing the bitrate cannot recover source detail.

Trim the clip and apply a short fade-in or fade-out before conversion to avoid an abrupt start or end. Use AAC audio in an MPEG-4 container, a lowercase or uppercase .m4r extension, and a clip no longer than the supported ringtone limit. If Apple software rejects the file, inspect it with a media-information tool and confirm that it contains AAC rather than FLAC, MP3, or another codec.