Calendar File Viewer & Editor guide

Create and export

Open local ICS files and choose the display timezone and date range.

Select a date or event. Edit the source event, change the selection or remove exact duplicates.

Review the range and export selected occurrences as ICS, CSV or an agenda PDF.

Supported formats and limits

ICS import: up to 10 files, 1 MB each, 5 MB total and 2,000 source events. Supports date-only, UTC, floating and IANA timezone events. Floating times use the chosen display zone. Common daily/weekly/monthly/yearly recurrence, COUNT, UNTIL, BYDAY, BYMONTHDAY, BYMONTH, limited BYSETPOS and EXDATE are supported. Unsupported recurrence, custom timezone IDs, RDATE and recurring overrides are rejected with a message, without importing a partial file. Alarms, attachments, URLs, attendees and custom metadata are omitted. Export contains explicit occurrences in the selected inclusive date range, up to 5,000, rather than unbounded recurring series. A multi-day event overlapping the range is included in full. Ambiguous/nonexistent daylight-saving wall times are rejected; use explicit UTC input for those cases. Calendar conflicts are time overlaps, not travel-time or resource-availability checks. All-day end dates are exclusive. Free events are excluded from conflicts; cancelled source events are omitted. Editing a recurring event changes its series; single-occurrence overrides are not supported. Export only includes checked source events. Exact duplicates compare title, dates, timezone, description, location, recurrence and exceptions, ignoring UID and filename.

Local processing

All files, events, names and notes stay in browser memory. No calendar-account connection, upload, external model, background reminders or automatic storage. Refreshing clears the workspace; save an export to keep your work. Exported calendar files require an explicit import into a calendar app; they do not create reservations or synchronize changes.