If you are comfortable with a command line, this is the purest "chip" method. It uses yt-dlp (the open-source successor to youtube-dl).
: Frequently appears in CHIP's "Top 5 Downloads of the Week" for its speed and ability to handle both MP3 and MP4 formats without registration. Important Safety Note chip youtube to mp3
: A clean, ad-free online tool that can convert videos up to 90 minutes long. If you are comfortable with a command line,