Teams & projects
Time zone overlap calculator
Enter your UTC offset and working hours, then your colleague's; get the window when you are both at work, shown in both local times.
Use the offset in force today, including daylight saving time (New York is −5 in winter and −4 in summer). An end time earlier than the start is read as a night shift.
How the overlap is calculated
Each workday is converted to UTC by subtracting the local UTC offset: a 9:00 start in UTC+1 is 8:00 UTC, and a 9:00 start in UTC−5 is 14:00 UTC. With both days on the same clock, the overlap is the later of the two starts to the earlier of the two ends. The calculator also checks the day before and after, so pairs such as Sydney and London, whose working days fall on different calendar dates, are handled correctly. The shared window is then converted back into each person's local time.
Example: you work 9:00–17:00 in Berlin in winter (UTC+1), which is 8:00–16:00 UTC. Your colleague works 9:00–17:00 in New York (UTC−5), which is 14:00–22:00 UTC. The overlap runs from 14:00 to 16:00 UTC: 2 hours, which is 15:00–17:00 for you and 9:00–11:00 for them, or a quarter of each workday.
| Pair (9:00–17:00 each, winter) | Offsets | Overlap |
|---|---|---|
| London – New York | 0 / −5 | 3 h |
| Berlin – New York | +1 / −5 | 2 h |
| London – San Francisco | 0 / −8 | 0 h |
| Berlin – Bangalore | +1 / +5.5 | 3 h 30 min |
| New York – São Paulo | −5 / −3 | 6 h |
| London – Singapore | 0 / +8 | 0 h |
Making a small overlap work
With an 8-hour day, any time difference of 8 hours or more leaves no overlap unless someone shifts their hours. Shifting is often cheaper than it sounds: if each side moves by one hour, a 9-hour gap gains a 1-hour shared window without anyone working outside a normal day. Agree on which side shifts and rotate it if the arrangement is permanent, so the inconvenience is not always carried by the same office.
Treat the overlap as the scarce resource it is. Use it for discussions that need back-and-forth, such as planning, unblocking and feedback, and move status updates and reviews to written channels that can be read later. A useful rule is to finish your day with a handover note so that the colleague who is still working can carry on without waiting for you.
Watch daylight saving time. Europe and North America change their clocks on different weekends in spring and autumn, so for a week or two each year the gap between them is one hour shorter, and the Southern Hemisphere changes in the opposite season. Re-check recurring meetings around those dates.
Frequently asked questions
How do I find overlapping work hours across time zones?
Convert both workdays to UTC by subtracting each UTC offset, take the later start and the earlier end, and convert that window back to each local time. If the later start is after the earlier end, there is no overlap.
What is the best meeting time for London and New York?
With 9:00–17:00 days on both sides, the shared window is 14:00–17:00 in London, which is 9:00–12:00 in New York, most of the year. It briefly changes when only one side has switched to summer time.
How do I enter time zones like India or Nepal?
Type the offset in hours with decimals: India is 5.5 (UTC+5:30) and Nepal is 5.75 (UTC+5:45). Negative offsets are for the Americas, for example −3 for São Paulo.