The .m4r is the extension of Apple iPhone ringtone files. You can purchase and download ringtones on Apple APP Store or other sharing sites, even make your own unique ringtones with the iPhone ringtone maker. But it's troublesome and inconvenient to share with friends, upload to sharing sites, play on other portable devices due to compatibility support. So it's necessary to convert M4R to MP3 format compatible with nearly all devices. To transcode M4R to MP3, here are two simple methods for free below.
1. M4R to MP3 Converter Software Input some words like "mp3 m4r converter", "m4r to mp3 convertor" in search engines, there are kinds of video converting freeware, not only support converting M4R to MP3, but also converting m4r to ogg, m4r to wma, m4r to aac, m4r to wav, etc.
2. Free Online Conversion Service Upload M4R file to some free online converting site like AudioConverto, Zamzar, Media.io, etc if you don't want to install software and have a high-speed Internet connection.