Kathmandu is 5.75 hours ahead of Reykjavik
Best overlap: 8:00 AM to 1:00 PM in Reykjavik is 1:45 PM to 6:45 PM in Kathmandu.
Shoot for 8:00 AM to 1:00 PM in Reykjavik; your Kathmandu colleagues will see that as 1:45 PM to 6:45 PM. Kathmandu is 5.75 hours ahead of Reykjavik, so the practical overlap is about 5 hours — generous enough for meetings, tight enough to be worth booking ahead.