How to use Calendar Conflict Checker

Supply supported finite calendar events.
Set the timezone policy for floating and all-day entries.
Review overlapping pairs and resolve any unsupported input before relying on the comparison.

Example: Calendar Conflict Checker

A local worked example using the inputs and settings below for calendar conflict checker.

You add

Calendars to compare: "text" First iCalendar text: "BEGIN:VCALENDAR\r\nVERSION:2.0\r\nPRODID:-//UseFreeTools//Finite calendar helper//EN\r\nBEGIN:VEVENT\r\nUID:[email protected]\r\nDTSTAMP:20260101T000000Z\r\nDTSTART:20260105T090000Z\r\nDTEND:20260105T100000Z\r\nSUMMARY:Planning meeting\r\nLOCATION:Room A\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n" Second iCalendar text (optional): "BEGIN:VCALENDAR\r\nVERSION:2.0\r\nPRODID:-//UseFreeTools//Finite calendar helper//EN\r\nBEGIN:VEVENT\r\nUID:[email protected]\r\nDTSTAMP:20260101T000000Z\r\nDTSTART:20260105T093000Z\r\nDTEND:20260105T103000Z\r\nSUMMARY:Review meeting\r\nLOCATION:Room A\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n" UTF-8 calendar files: ["sample.png (348 bytes)"] Zone for floating times and all-day dates: "UTC" Repeated local clock policy: "earlier"

You get

Options

Comparison inputs: Paste the two supported calendar texts or choose the intended files. Only supplied finite event intervals are compared.
Default zone and repeated time: These controls affect supported local-time interpretation. UTC and all-day values follow their separate conventions.

Supported inputs and limits

Up to eight files, 5 MiB combined and 200 event records; dates 1970–2100. Recurrence, custom embedded timezone rules, unresolved endpoints and unsupported semantics are refused. Cancelled, transparent and zero-duration records do not block time and are reported. Adjacent endpoints do not overlap; matching UIDs across calendars are not merged.

Where your input is processed

This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

Touching endpoints are different from overlap

An event ending when another begins does not overlap under the stated exclusive-end interval model. A conflict report does not assess travel time, setup time, attendee availability or recurrence that the parser refuses. Add necessary buffers to the event data before using it to plan a schedule.

Questions about Calendar Conflict Checker

Are adjacent events conflicts?

No. An event ending at the next event’s start does not overlap under this half-open interval model.

Can recurring events be ignored?

No. Unsupported recurrence prevents a complete supported conflict result. Supply an appropriate finite event export.

Does a conflict change either calendar?

No. The page reports pairs for review and does not edit an account or original file.

Project manager: Tony Hines · Content updated 4 October 2026 · Report a problem