World clock board
One instant, every clock
A zone is not an offset. It is the set of rules that produce one. Scrub the slider to find a meeting slot, or type an instant to see how the board looked then.
How the board works
The board shows one moment in every city you add. It starts on now, with Los Angeles, New York, London and Kolkata. Add any zone your browser knows, drop the ones you do not need, and the board keeps your list on this device.
Each row shows the local time, the date, the offset from UTC and whether that zone is on daylight saving time right now. It also shows when the clocks there next change. That matters, because two cities that are five hours apart today may be four hours apart next week.
Below the board is the meeting planner. It lays out one day as 24 columns, one for each hour on your own clock. A green bar counts how many cities are inside working hours at that hour, so the tallest bars are the best times to meet. Click a column and the whole board moves there. You can set the working day yourself.
The board, the time and the working hours all live in the address bar. Send the link and the other person sees the same board.
Questions people ask
Why is a zone not the same as an offset?
An offset like UTC+1 is a single number. A zone like Europe/London is a set of rules that picks the offset for each date. London is UTC+0 in winter and UTC+1 in summer, and the zone knows when it switches.
How do I find a good meeting time?
Add every city that will join. Then look at the planner under the board and pick the hour with the tallest green bar. That is the hour when the most people are at work.
Where does the time zone data come from?
From the IANA time zone database built into your browser. It is the same data your phone and computer use, and it is kept up to date with each browser release.
Can I see the board at a time other than now?
Yes. Type an instant or scrub the slider, and every city moves to that moment. It is a quick way to check what a past or future meeting looked like for each person.