This URL is the cancellation page — you do not have to hunt through settings
Go to the YouTube Premium cancellation page
https://www.youtube.com/paid_memberships
Cancelling does not cut you off immediately. You keep access until the end of the period you already paid for, so if you have decided not to renew you can cancel straight away without losing anything.
If you subscribed through the App Store on an iPhone, cancel in iOS under “Settings → Apple ID → Subscriptions”. You cannot cancel it on the YouTube website.
The same applies if you subscribed through a mobile carrier plan — go back to where you signed up.
Prices verified , with the official page as the final word. Plans and availability vary by region; these are the official Taiwan prices.
People who forget to cancel are not careless — the moment you decide and the moment you are charged are a whole month apart. Add LapseWatch on LINE and send “YouTube Premium 12/25” to record it. No install, no signup.
Want to see the whole picture? Add up a year of subscriptions (in Traditional Chinese); if you work at a computer there is also a Chrome extension that keeps everything on your own machine.
Interfaces change. Always treat the official page as the final word.