If the calendar's server blocks direct requests (CORS), the link is fetched through this site's own proxy instead. Pasted and uploaded calendars never leave your device.
Structural and semantic checks follow RFC 5545. The text is also run through Mozilla's ical.js parser, and every RRULE is parsed with ICAL.Recur.
What this does
Calendar apps share events as iCalendar data: an .ics file or a calendar link. If that data contains mistakes, apps like Google Calendar, Outlook or Apple Calendar may refuse it, skip events, or show the wrong times.
This tool reads a calendar, checks it against the official iCalendar rules (known as RFC 5545), and tells you in plain words what is wrong and on which line.
How to use it
- Give it a calendar. Paste a calendar link on the URL tab, drop an .ics file on the Upload tab, or paste the text on the Paste tab.
- Click Validate.
- Read the result. A green card means the calendar is valid. A red card means there are errors to fix.
Not sure what to expect? Open Examples and load one.
What the results show
- Source: the calendar line by line. Lines with errors are red and lines with warnings are yellow.
- Issues: every problem found. Errors break the rules and should be fixed. Warnings are allowed but can cause trouble in some apps. Notes are for information.
- Inspector: what the calendar contains, with its events as a table or on a month calendar.
- Copy or Download the report to share it.
Privacy
Files you upload or paste are checked inside your browser and are never sent anywhere. A calendar link is fetched straight from its server. If that server blocks the request, the link is fetched through this site's own small proxy, which passes the file back and stores nothing.
Component counts
Events
| Summary | Start | End / Duration | Location | Recurrence | Status | UID |
|---|