🌍 Time Zone Meeting Planner

Finding a call time across time zones is a subtraction problem that daylight saving keeps changing. Add the cities, pick the date, and the grid shows what the clock actually says in each place — then the summary names the best overlap instead of leaving you to count rows. Every offset comes from the IANA time-zone database already inside your browser: no API call, no account, no guessed offsets.

Green is 09:00–17:59 · amber is 07:00–08:59 or 18:00–20:59 · everything else is somebody’s night. The colours are a convention, not a law: shift workers, Fridays and half-day offices exist.

How to use it

Set the date to the day you are proposing, keep your own zone as the base, then add the other places one at a time. Each column shows that city’s clock for the same instant, with its true UTC offset printed in the header. The Work hours column counts how many of your cities are between 09:00 and 17:59; the summary above the table finds the longest stretch where every city is inside it, and when no such hour exists it says so plainly and reports the closest one — including who is at 23:00.

Two habits make the result honest. First, a meeting that is comfortable for five of six cities is still a meeting somebody takes at midnight, so rotate the awkward slot between regions rather than always giving it to the same team. Second, the date matters as much as the hour: a slot that works in March can break in April because one country moved its clocks and another did not.

Why the maths is trustworthy, and where it stops

Time zones are not whole-hour offsets. India is +05:30, Nepal +05:45, Chatham Islands +12:45 and Lord Howe switches between +10:30 and +11:00 — none of which survives mental arithmetic on UTC+5. The browser’s Intl data knows all of them, including the historical rules, so this page never adds “one hour per zone”.

What the browser cannot know is a change made after your copy of the time-zone database was built. Governments do alter rules at short notice (Chile, Mexico, Iran, Russia and Egypt have all done it this decade), and a browser that has not updated can be weeks behind. For a meeting next week that is irrelevant; for a booking across a known transition date, confirm with a local calendar. On a spring-forward day one wall-clock hour does not exist, and this grid shows the instant’s real clock time rather than inventing a 02:30 that nobody lived through.

Part of Everyday Tools. Converting a single timestamp instead? The Unix timestamp converter handles epoch to date and back.