Check itinerary time conflicts and overlapping activities

Add each activity with a name, start time, and end time in 24-hour HH:MM format. The result shows whether conflicts exist, how many were found, which activities collide, and the exact shared time window. It also rejects an activity whose end is earlier than its start, preventing an invalid schedule from producing misleading conflict results.

Enter a clear same-day itinerary

Give every activity a useful name and enter its start and end in 24-hour HH:MM format. The checker treats all entries as belonging to the same day, which makes it well suited to a sightseeing plan, conference agenda, day trip, group tour, or travel-day checklist. Use names that remain recognizable in the result, especially when several bookings have similar times. For example, “Museum guided tour” is more useful than “Tour” when the conflicting item is “Old Town walking tour.” The input order does not need to be chronological. The checker compares all pairs and retains each activity’s original zero-based index, so an automated system can connect a reported conflict to the submitted record without guessing. An end time may equal its start time; that represents an activity with no duration and creates no overlap. An overnight activity is outside this capability’s same-day model because an end such as 01:00 after a start at 23:00 appears reversed. Split overnight plans by date or use explicit dated scheduling before checking them here.

Understand exactly what counts as a conflict

Two activities conflict only when they share a positive amount of time. If a museum visit ends at 11:00 and lunch begins at 11:00, they touch at the boundary but do not overlap. If lunch begins at 10:59, the pair conflicts for one minute. For every collision, the output identifies both activity names and indexes, the start and end of their shared window, and the overlap length in minutes. This pair-based reporting is deliberately complete: when three activities occupy the same period, the result contains all three conflicting pairs rather than merging them into one vague block. That makes the answer useful for both people and software because each booking relationship can be reviewed independently. Conflicts are returned in deterministic input-pair order, not ranked by severity. An activity fully contained inside another is still one conflict, with the contained activity’s entire duration as the overlap window. Identical time ranges also conflict for their full duration. These rules match the practical question of whether attendance at both planned items is possible without being in two places during the same minute.

Fix invalid ranges and use the result

Before comparing activities, the checker validates every time. A value must have two hour digits, a colon, and two minute digits, using the 00:00 through 23:59 range. It also stops with an input error if any end time is earlier than its start time. That fail-fast behavior matters because silently treating a reversed range as overnight, empty, or automatically corrected could hide a booking mistake. Once the input is valid, start with `has_conflicts` for a simple workflow decision. Use `conflict_count` to summarize the schedule and inspect `conflicts` to show actionable details beside the original activities. A travel planner might ask the traveler to choose between each pair, while a spreadsheet or booking pipeline could flag the referenced indexes for revision. After changing the itinerary, submit the complete list again; a result with zero conflicts confirms that no positive-duration overlaps remain under the same-day rules. The calculation is deterministic, uses no network or current clock, and returns the same answer for the same ordered input. Browser use is free, while an automated API request uses the published base price of $0.002.