Reykjavik is 5 hours behind Karachi
Best overlap: 1:00 PM to 6:00 PM in Karachi is 8:00 AM to 1:00 PM in Reykjavik.
Aim for 1:00 PM to 6:00 PM Karachi time — that's 8:00 AM to 1:00 PM over in Reykjavik. Reykjavik is 5 hours behind Karachi, leaving about 5 hours of daily overlap — enough for most meetings if you don't leave them too late in the day.