Best overlap: 8:00 AM to 1:00 PM in Manchester is 1:00 PM to 6:00 PM in Karachi.
For the smoothest call, aim inside 8:00 AM to 1:00 PM in Manchester, i.e. 1:00 PM to 6:00 PM in Karachi. Karachi is 5 hours ahead of Manchester, so the practical overlap is about 5 hours — generous enough for meetings, tight enough to be worth booking ahead. Seasonal note: Manchester uses daylight saving and Karachi doesn't, so double-check the times in your own months — they can move by an hour.
London to New York is five hours apart, except for the five weeks a year when it isn't. Exact overlap windows for every US zone, the 2026 DST mismatch dates, and where to put the recurring sync. -