Caspian Office

Time zone planner

Compare a time across your zone and cities around the world, with a working-hours strip that lines up overlapping slots so you can pick a meeting time. Uses the time-zone data built into your browser, fully offline.

Open Time zone planner →
Private · runs in your browserOffline · after first loadFree · no signup

What is the time zone planner?

A free, private meeting planner that compares one moment across your zone and any cities you add around the world. Each zone gets a 24-hour strip that shades working hours so overlapping slots line up vertically, making it easy to pick a time that suits everyone. It uses the time-zone data built into your browser, runs entirely on your device and keeps working offline.

How to use Time zone planner

  1. Add the cities you need — Type a city or IANA zone into the search box and click Add. Your own zone appears at the top, marked YOU.
  2. Pick the date — Set the date with the picker, or click Now to jump to the current day and time.
  3. Choose an hour — Click any cell in the strip to set the time. Every other zone updates to show the matching local hour and weekday.
  4. Read the overlap — Green cells are working hours (9 to 17). Where the green lines up across all the rows is a good slot to meet.

Frequently asked questions

Does it handle daylight saving time?

Yes. It uses your browser's built-in IANA time-zone database, so daylight saving shifts and historical offsets are applied automatically for each city.

Are my saved cities kept private?

Yes. The list of zones is stored only in your browser's local storage on this device. Nothing is sent anywhere, and it all works offline.

What do the cell colours mean?

Green marks core working hours (9 to 17), amber marks the fringe (early or late), and dark cells are night-time. Line up the green cells to find a comfortable meeting window.

Why does a city show a +1 or -1 day label?

When a zone is far enough ahead or behind yours, the chosen hour falls on a different calendar day there. The label tells you how many days apart it is.

Will my added cities still be there next time?

Yes. Your zones persist on this device, so the planner reopens with the same cities you were last comparing.

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