3 tools for convert youtube to mp3

1. 1conv.com

The link is as follows:convert youtube to mp3
the advantage is simple and fast, it can detect subtitle intelligence. If the language of subtitles are not what you want, you can try the link suppose you are japanese,and another advantage is website won't limit the download speed.

2. mp3-youtube.download

The link is as follows:convert youtube video to mp3
it is compatible with other popular websites besides youtube, The flaw is you have to see ads when click download button.

3. Any Audio Converter

Any Audio Converter
It is developed for converting YouTube to MP3. Convert music video from YouTube to MP3 audio files of best possible quality with no limits on the amount of conversions and downloads. But first you need download the software.

Notice: download videos and mp3 must be licensed by the version owner and used only for study and research, and not for commercial use and dissemination.