Ytmp3 is an excellent Youtube to MP3 Converter, the purpose is to make it easy for users to convert YouTube videos to mp3 or mp4, and download them to their mobile phones or car devices, so that they can still be listened to when there is no network. Want to listen to YouTube music.

4K Video Downloader is another great option if you are looking to install software to download YouTube videos and convert them to MP3 or MP4 but if you want it to be fast try btclod its free