Project Management Tools
Critical Path Calculator
List your tasks, durations, and dependencies and get the full critical path method (CPM) analysis — earliest and latest start times, float for every task, the critical chain that sets your end date, and the total project duration.
Task list
Give each task a duration in working days. In Depends on, list the IDs of the tasks that must finish first (comma-separated, e.g. A, C). Leave it blank for starting tasks.
| ID | Task name | Duration (days) | Depends on |
|---|
Reference
How the critical path method works
CPM finds the longest chain of dependent tasks in your project. That chain — the critical path — determines the minimum project duration. Everything else has float.
What the numbers mean
| ES / EF | Earliest start and finish, found by a forward pass: a task can start as soon as all of its predecessors are done. |
| LS / LF | Latest start and finish that still hit the project end date, found by a backward pass from the final task. |
| Float | LS − ES. The number of days a task can slip before it delays the project. Zero float = critical. |
| Critical path | The chain of zero-float tasks from start to finish. Its length equals the total project duration. |
Using it well
- Estimate durations in working days and keep them honest — padding hides the real critical path.
- Watch near-critical tasks (1–3 days of float). Small slips can flip the critical path to a different chain.
- Crash or fast-track only critical tasks — shortening anything else spends money without moving the end date.
- Re-run the analysis whenever scope or dependencies change; the critical path moves more often than teams expect.
- This model assumes finish-to-start dependencies with no lead/lag — the standard planning baseline.
Want this schedule managed, not just calculated?
A critical path is only useful if someone defends it. If you want an experienced engineer building and protecting your program schedule, bring your task list to a consultation.
Schedule a consultation