Compare live local time difference, overlapping working hours, flight distance, and sunrise/sunset between any two world cities.
Automatic calculation of seasonal daylight saving time shifts using the global IANA database.
Shared working hours (09:00–18:00) between both cities highlighted in vivid emerald green.
Great-circle distance, approximate direct flight duration, and live sunrise/sunset comparison.
The difference is determined by comparing each city's official IANA time zone offset from Coordinated Universal Time (UTC). For example, if Istanbul is at UTC+3 and New York is currently at UTC-4 (EDT), the difference is exactly 7 hours. Our calculator automatically handles seasonal transitions.
Yes. Because regions transition to and from Daylight Saving Time on different calendar dates (or do not observe DST at all), the time difference between city pairs like New York and London or Berlin can temporarily expand or shrink by 1 hour during transition weeks.
The optimal window is when both parties fall within standard business hours (09:00–18:00 local time). Our 24-hour visual comparison highlights these shared hours in vivid emerald green, making it easy to schedule international conferences and calls.
Traveling east compresses your day, forcing your circadian clock to advance faster than its natural cycle, whereas flying west extends your day, which the human biological rhythm tolerates more easily.