Oppo
Change Default Event Duration in Calendar auf Oppo
New events in the Google Calendar app on Oppo phones usually get a fixed default length, often one full hour, even when you only add a short reminder or a quick call. This setting lives inside the calendar app itself, not in the ColorOS system settings, which is why changing display or notification options never affects it.
If several accounts are linked to your calendar, such as a private and a work Google account, each one keeps its own default duration. Fixing the setting for one account will not automatically change it for the others.
To adjust it, open Tap on Calendar ➔ Open the Menu ➔ Tap on Settings ➔ Tap on General ➔ Tap on Default event duration. From there, Choose an Account if more than one is linked, then Choose an Option for the new default length.
This only changes newly created events going forward. Existing entries in your calendar keep their original duration and need to be edited individually if they are wrong.