Copenhagen is 7 hours behind Shanghai
Best overlap: 3:00 PM to 6:00 PM in Shanghai is 8:00 AM to 11:00 AM in Copenhagen.
Plan around 3:00 PM to 6:00 PM in Shanghai, which is 8:00 AM to 11:00 AM in Copenhagen, to catch everyone during office hours. Since Copenhagen is 7 hours behind Shanghai, the workdays overlap by around 3 hours; 3:00 PM in Shanghai (8:00 AM in Copenhagen) makes a reliable recurring slot. For part of the year the maths changes: Copenhagen observes daylight saving, Shanghai does not, shifting the overlap by an hour.