ICS Calendar Viewer
Paste an .ics file or pick one from disk, then press Parse calendar: the entries, the calendar properties and every issue found stay in the page and can be copied or downloaded as JSON.
Runs locally in your browser ·
Paste an .ics file or pick one from disk, then press Parse calendar: the entries, the calendar properties and every issue found stay in the page and can be copied or downloaded as JSON.
Runs locally in your browserPaste an .ics file into the box or pick one from disk — up to 5 MB, with the size shown next to the file name — and press Parse calendar. The calendar is read in the tab, so nothing is sent anywhere, and the JSON export works the same way. The summary names the calendar, its PRODID and version and counts the events, tasks and issues found; every entry appears below as a card with its date, location, RRULE text and description.
A file only has to be close to iCalendar to be useful here. Lines are unfolded first, so a continuation line starting with a space or tab joins the one above it; property names may be lower case; CN="Doe; John" keeps its semicolon inside the quoted parameter; and \, \; \n and \\ are decoded before a value is shown. A line the parser cannot split into a property and a value is reported with its number instead of stopping the whole file.
Four date shapes are read: 20260901T090000Z as UTC, 20260901T090000 as a floating local time, 20260901 as an all-day date, and a zoned value carrying a TZID parameter. The zone name is printed next to the value — DTSTART;TZID=America/New_York:20260901T090000 shows as 2026-09-01 09:00:00 (America/New_York) — and the clock time stays exactly as written, because the page has no time-zone database to convert it with. A value that fits none of those shapes is reported in the Issues row with its property name and raw text.
All-day entries print as dates. An event without DTSTART shows a dash where the date would be, and the issue list names the missing field.
VEVENT and VTODO are kept apart: an event card carries its date range, location, RRULE text and description, a task card carries its due date. A property that appears more than once keeps every value (two ATTENDEE lines export an array), and nested components such as VALARM travel with their parent under components in the JSON.
RRULE is exported as text and not expanded: a weekly rule with COUNT=6 stays one event with the rule written out in full.
This is a reader with a short checklist, not a conformance test. It checks the fields named above and the shape of the file; it does not walk RFC 5545 property by property, it does not fetch a subscription URL, and it does not repair a damaged file. What it cannot read or split is named with the line number or the entry it came from, so a file that half-parses can be fixed exactly where it broke.