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Klargantt

Calculate the critical path of a schedule

Drop the schedule. Early and late dates are computed, float follows, and the critical path is drawn in red on the chart. The task holding the project finish is named.

Drop a schedule file

Microsoft Project XML, Primavera P6 XER, GanttProject .gan, CSV or .xlsx table, .mpp recognised. Or

When to use it

The schedule you received shows a critical path, and you want to check it before committing to it.

Or it shows none, because it was drawn by hand, with no links between tasks.

Or a task has slipped, and you need to know whether the project finish moves.

What this page does

  • Forward and backward passes, across the four link types and their lags.
  • Project's eight constraints, deadlines, manually scheduled tasks and progress are all taken into account.
  • Total float and free float, in working hours then converted to working days of the relevant calendar.
  • Negative float is shown as such, never clamped to zero.
  • Summary tasks carry the roll-up of their descendants, without being scheduled themselves.

What it does not do: The calculation is not presented as identical to Project's or P6's. It is shown beside the file's dates, with the gap task by task. Resource levelling is not performed, and an overload moves nothing.

What is read

  • Microsoft Project XML, Primavera P6 XER, GanttProject .gan, a CSV or .xlsx table.
  • Project, task and resource calendars, with their exceptions and public holidays.

No file is uploaded: the schedule is read by your browser, in this tab, and the page is not allowed to open a connection to any other site.

Frequently asked questions

What makes a task critical?
Total float at zero or below: any delay on it moves the project finish. The critical path is the chain of those tasks, from start to finish.
Why does my critical path differ from the one shown in Project?
Usually because of a hard constraint, a deadline, or a manually scheduled task. The workshop shows the gap task by task, which is where the divergence starts.
Do I need links between tasks?
Yes. A schedule with no links has no critical path: it has bars placed by hand. The quality check reports it.

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