Software & Apps File Types What Is an M4R File? How to open, edit, & convert M4R files Share Pin Email Print File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More By Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated September 21, 2019 A file with the M4R file extension is an iTunes Ringtone file. They can be created and transferred to an iPhone to use custom ringtone sounds. Custom iTunes Ringtone files in the M4R format are actually just .M4A files that have been renamed to .M4R. The file extensions are different only to differentiate their purposes. How to Open an M4R File Open M4R files with Apple's iTunes program. M4R files that aren't copy protected can be opened using the free VLC software and other media players. To the M4R ringtone with a different program, try renaming the .M4R extension to .MP3 before you open it. Most media players recognize the MP3 format but they may not support loading files that have the .M4R extension. Some files have a similar file extension as .M4R but that doesn't mean that the formats are related. For example, M4Es are video files, M4Us are playlist files, and M4s are Macro Processor Library text files. If you can't open your file as an audio file, double-check that you're reading the file extension correctly. If you find that an application on your PC does try to open the M4R file but it's the wrong application or if you would rather have another installed program open M4R files, change the default program for a specific file extension. How to Convert an M4R File You're probably not looking to convert an M4R file to another format, but instead to convert a file like an MP3 to the M4R format so that you can use the file as a ringtone. Convert with iTunes by following these steps at Switching to Mac. What you're doing is converting an M4A or MP3 file from your iTunes library to M4R, and then re-importing the file back in to iTunes so that your iPhone can sync with it and copy over the new ringtone file. Not every song downloaded through iTunes can be used as a ringtone; only those that are specially marked as supporting the format. Several free audio converter software programs convert to and from the M4R format. FileZigZag and Zamzar save the file to formats like MP3, M4A, WAV, AAC, OGG, and WMA.