Karachi is 5 hours ahead of Reykjavik
Best overlap: 8:00 AM to 1:00 PM in Reykjavik is 1:00 PM to 6:00 PM in Karachi.
Schedule calls for 8:00 AM to 1:00 PM in Reykjavik — your colleagues in Karachi will be online from 1:00 PM to 6:00 PM. Karachi is 5 hours ahead of Reykjavik, leaving about 5 hours of daily overlap — enough for most meetings if you don't leave them too late in the day.