Istanbul is 1 hour ahead of Bucharest
Best overlap: 8:00 AM to 5:00 PM in Bucharest is 9:00 AM to 6:00 PM in Istanbul.
Aim for 8:00 AM to 5:00 PM Bucharest time — that's 9:00 AM to 6:00 PM over in Istanbul. Istanbul is 1 hour ahead of Bucharest, but you still share a generous 9 hours of overlap, so scheduling is easy and there's room to move a meeting when you need to. These times hold for most of the year, but Bucharest's daylight saving (which Istanbul doesn't use) shifts them by an hour twice annually.