If you're here you probably know how this works, but here's the general rundown:
STEP 1: Grab a YouTube video URL
(Example: https://www.youtube.com/watch?v=dQw4w9WgXcQ)
STEP 2: Paste it in the textbox above
STEP 3: Select the video format you want it in (MP4/M4A/MP3)
STEP 3.5: Select video quality if downloading an mp4
STEP 4: Click Convert and Profit :D