About this tool
Turn an explicitly selected source wall time into one real instant, compare the local result for each participant, and export the same instant for calendar import.
Time Zone Meeting Planner starts from one wall-clock time in one source zone and shows what that same moment looks like for up to eight other IANA zones, then writes it out as a calendar file. The source date, 24-hour time, and duration (1 to 1,440 minutes) are resolved with the browser's own time-zone rules, so daylight-saving shifts are handled by real data rather than a fixed offset. For every zone the table lists the local start, local end, UTC offset, and whether the meeting lands on the previous or next calendar day. The export is a single UTC VEVENT in a meeting.ics file, checked for CRLF line endings, 75-octet folding, and required properties before the download is offered.
- Validates a 1900-9999 Gregorian date, 24-hour wall time, 1 to 1,440 minute duration, source zone, and 1 to 8 unique browser-supported participant IANA zones.
- Rejects skipped DST times, requires an earlier or later choice for repeated times, and shows local start, end, UTC offset changes, and calendar-date differences.
- Exports one UTC VEVENT with bounded title, location, HTTP(S) URL, and description after CRLF, required-property, UTF-8 75-octet folding, and component checks pass.
How to use Time Zone & ICS
Enter a meeting title (up to 200 characters), pick the date and time, and set Duration minutes. Choose the Source time zone; the form defaults to Asia/Seoul with today's date. Add participants by typing an exact IANA identifier such as Europe/Berlin into the Add exact IANA time zone field and pressing Add zone; duplicates, the source zone itself, and unrecognized names are rejected with a message, and each added zone has its own Remove button. If the chosen local time does not exist because clocks moved forward, the planner blocks it. If it occurs twice during a fall-back hour, radio buttons ask for the Earlier occurrence or Later occurrence. Optionally fill in Location, an HTTP(S) Meeting URL, and a Description, then press Download ICS.
When this tool is useful
- A remote team lead scheduling a design review across Seoul, London, and New York who needs each person's local start and end.
- An event coordinator sending a calendar invite that must import correctly into Google Calendar, Outlook, and Apple Calendar.
- A support manager confirming that a 9:00 handover in Sydney does not land on a different calendar day for the Berlin team.
- A freelancer double-checking a client call booked in the week the United States and Europe change clocks on different dates.
- An operations engineer documenting a maintenance window as a single UTC instant rather than several local times.
Practical tips
- Watch the offset column when a meeting is set in early November or late March; the source and participant offsets may differ from last week's.
- The date-difference label is the easiest way to catch a meeting that falls on Saturday for an Asia-Pacific participant.
- Type IANA names exactly, such as America/Sao_Paulo; city nicknames and abbreviations like PST are not accepted.
- The file stores one UTC instant with no recurrence rule, so a weekly series still has to be created in the calendar app.
- Import the downloaded meeting.ics into the actual destination calendar and compare the displayed time before sending it to anyone.
Examples you can test
Load an example, compare the result with the expected output, then replace it with your own input.
Three-zone review
Example input
2026-03-12 09:00 Asia/Seoul, 60 minutes, participants America/New_York, Europe/London, Asia/Tokyo
Expected output
New York 20:00 to 21:00 on 2026-03-11 (UTC-4, previous day), London 00:00 to 01:00 on 2026-03-12 (UTC+0), Tokyo 09:00 to 10:00 (UTC+9)
New York is already on daylight time on March 12 while London is not, which is why the gap between them is only four hours.
Repeated fall-back time
Example input
2026-11-01 01:30 America/New_York, 30 minutes
Expected output
The planner reports that 01:30 happens twice and requires Earlier occurrence (UTC-4) or Later occurrence (UTC-5) before Download ICS is allowed
Daylight time in the United States ends on the first Sunday of November, so 01:00 to 01:59 repeats on that date.
Validation checklist
- Confirm the source zone owns the wall-clock time you typed.
- Check each participant's local date, not just the hour.
- Resolve any earlier or later occurrence prompt before exporting.
- Open the .ics in the destination calendar and compare the shown start time.
- Make sure the meeting URL begins with http or https and is under 2,048 characters.