Decompose scope, then sequence the work
Critical Path, Float and Schedule Compression
How to find the sequence that actually determines your end date — and what to do about it.
On this page
The critical path is the longest sequence of dependent activities through the network. Its length is the shortest possible project duration, and every activity on it has zero float.
Calculating it
- 1Forward pass — walk the network computing early start and early finish for every activity.
- 2Backward pass — walk it in reverse computing late start and late finish.
- 3Total float = Late Start − Early Start. Activities with zero total float form the critical path.
| Technique | Mechanism | Cost |
|---|---|---|
| Crashing | Add resources to critical activities | Higher cost, diminishing returns |
| Fast tracking | Overlap sequential activities | Higher risk and rework |
| Scope reduction | Remove work from the path | Reduced deliverable |
Related PMI standards & templates
External resources on pmi.org — links open in a new tab. Some require PMI membership.
PMI standard templates for this topic
Editable Word and print-ready PDF downloads — no sign-up required.
- Project plan pack template →A PMI standard project plan template pack: the nine-section plan document plus a schedule worksheet with duration, dependency, float and milestone tabs.
- RAID log template →A PMI standard RAID log template with risks, assumptions, issues and dependencies in one register, a 1-25 scoring key and a filled-in example you can copy.
The PM Delivery Toolkit turns everything in this guide into fill-in templates — $25, one payment.
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