WhenMathMulti-Timezone Event Planner
Enter one event's date, time, and source zone, then list every other zone you need it rendered in. See the local date and time in each, including any date shift.
Worked example
A 09:00 America/New_York event renders as 14:00 the same calendar day in Europe/London, once both zones' actual offsets on that specific date are applied to the underlying instant. Add a third target zone far enough away, such as Asia/Tokyo, and the same event renders as 23:00 that evening in Tokyo, still the same calendar day there. Push the event later in the day instead, say to 22:00 New York time, and the Tokyo rendering can roll onto the following calendar date entirely, which the planner shows plainly rather than only changing the clock time and leaving the date unchanged.
Common mistakes
- Forgetting that an event can land on a different calendar date in a zone far enough away, not merely show a different clock time on the same date.
- Entering a target zone using an abbreviation instead of a real IANA zone name, which can be ambiguous across regions that reuse the same abbreviation.
Limitations
Up to 20 target zones are supported per event. This renders a single event only. It does not build a recurring schedule across multiple dates. See the Recurring Date Generator for that.
Frequently asked questions
- Can I export the full list of rendered local times?
- Yes, the download CSV button exports every target zone along with its own rendered local date and time for the event.
- How many target zones can I add for one event?
- Up to 20, which comfortably covers a globally distributed team or audience without the list becoming unwieldy to review.