Open the video in the YouTube app or website, tap or click Share, then choose Copy link.
Go to the YTDownloader home page in Chrome, Safari or any browser. There is nothing to install.
Tap the Paste button (or press Ctrl+V) to drop the link into the box, then hit Download.
Choose an MP4 video from 360p up to 1080p with sound, or switch to the Audio tab for MP3 and M4A. Press Download next to the one you want and the file saves to your device.
Links that end in a timestamp (&t=90s) or come from a playlist (&list=...) are fine. The tool only reads the video ID.
1080p looks best on a laptop or TV. 480p is plenty for a phone screen and takes about a third of the space.
Tap the Share arrow on the right side of a Short, copy the link and paste it the same way. The video keeps its tall 9:16 shape.
Check that the video is public. Private, members-only and age-restricted videos cannot be saved. On iPhone, use Safari rather than Chrome.