Meeting time overlap
Find working-hour overlaps across time zones.
How to use
Enter two or three time zones and the working hours that count as reasonable, from a start hour to an end hour (9 to 17 by default). Find overlap today checks every hour of the current day and lists the hours that fall inside everyone’s working day, in UTC and in each zone’s local time.
Time zones are written as names from the IANA time zone database, the same names phones and calendars use: Europe/Lisbon, Europe/London, America/New_York, America/Sao_Paulo, Asia/Tokyo. A city name on its own, or an offset such as UTC+1, is not accepted, because neither says how the clocks change during the year. The same working hours apply to everyone, and the check works in whole UTC hours; zones with a half-hour offset, such as Asia/Kolkata, are shown with their local minutes.
Daylight saving is applied per zone, using today’s date, which is where most meeting maths goes wrong. Europe and the United States change on different dates, so the gap between them is an hour smaller for two to three weeks in March and about one week around the end of October; the southern hemisphere shifts the other way, and Brazil abolished daylight saving in 2019. Run the check again near the date of the meeting.
If no hour fits everyone, the tool says so: widen the working hours, or accept that one side meets early or late. Everything is calculated in your browser.
Example
Europe/London + America/New_York, 09–17, in early OctoberThree shared hours: 13:00–16:00 UTC, which is 14:00–17:00 in London and 09:00–12:00 in New York.Europe/Lisbon + America/New_YorkFive hours apart most of the year, four for a few weeks in spring and autumn.Europe/London + America/Sao_PauloFour hours apart in the British summer, three in winter, because Brazil no longer changes its clocks.Europe/Lisbon + Asia/Tokyo, 09–17No overlap: the working days are eight or nine hours apart.
Frequently asked questions
Why does the difference between two cities change during the year?
Because each country decides when its clocks move, and some do not move at all. The gap between Europe and the United States narrows for a few weeks each spring and autumn, when one has changed and the other has not.
Which clock should a recurring meeting be set in?
In a named time zone rather than a fixed offset. Calendars that store Europe/Lisbon follow the rule changes; ones that store UTC+1 drift the moment a country moves its clocks.
Why is my time zone rejected?
It must be a name from the IANA database, usually a region and a city joined by a slash, with underscores for spaces: America/New_York, not New York. Capitals do not matter.
Can I give each person different working hours?
Not in this tool: the same hours apply to every zone. Use the widest range that works for everyone and read the local times in the result.