November, 2017: Google Calendar offered me a new look. I tried it and would like to revert to the previous version. I checked the help pages and read that I should click on the little gear icon and then would see "Back to classic Calendar." But I don't have a little gear icon, and when I go to Calendar Settings, I don't see a way to return to classic calendar.
This might be a result of your viewport size. The "gear/settings" icon only appears intermittently at top right for select viewports.
It appears between 530 - 600px and above 800px. You could try zooming in or out to force it to appear and be toggle-ready.
-
3