Campaign Timezone Planner
Dated IANA timezones, 40 shortcuts, ambiguous/nonexistent DST handling and ICS.
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Projects stay in this browser. Save a backup before changing devices. Use the export format offered by each tool.
From your inputs to a usable result
01
Enter one dated event
Choose the event location, local date and time, and elapsed duration. Forty named IANA shortcuts use the bundled 2026e timezone snapshot.
02
Resolve the clock and compare locations
Choose the exact UTC occurrence when a local time repeats. A skipped time stays unresolved until you change it. Compare start and end clocks for up to twelve audience locations.
03
Keep exact instants
Export one calendar event as ICS with UTC timestamps, all comparisons as CSV or TXT, or a JSON project backup. Calendar import is manual; the app sends no invitations.
Before you start
Where is my project saved?
Projects are saved in this browser for this site account. Download a JSON backup before changing devices or clearing browser storage.
Which timezone rules are used?
The app bundles IANA 2026e rules for forty named locations and event dates from 2020 through 2050. Results do not depend on the browser timezone database. Governments can change future rules, so review important dates after a source update.
What happens when a local clock time repeats or is skipped?
Repeated times show their distinct UTC instants and offsets; you must choose one. A skipped local time has no matching instant and blocks export. The app never silently shifts the entered time.
Is duration measured on the local clock?
Duration is real elapsed time. An offset change during the event can make the local end clock look earlier or later than expected. Both start and end offsets are shown.
Does the ICS file schedule or invite anyone?
No. It contains one event for manual import, with UTC start and end timestamps. Your calendar displays it in its chosen timezone. Reimport behavior depends on the calendar; no attendee invitations are included.
Can I preserve the same result in a backup?
The backup includes the exact timezone snapshot and selected occurrence. Existing projects retain that snapshot. Calendar event identity follows the saved project; importing a backup as a new project creates a different identity.
Can I resume later?
Reopen the saved project on this browser and account, or restore its JSON backup. Keep backups in a place you trust because they include your supplied material.