Purpose and scope
What this schedule planner builds
Add project and feeding buffers to an entered critical-chain schedule.
The Critical-Chain Buffer Calculator keeps Project starts, Critical-chain duration days, Project buffer percent, Feeding chains, and Feeding buffer percent visible beside the result so the inputs can be checked, saved, and reproduced without reconstructing the calculation later.
Instructions
How to use this calculator
Enter the values requested for the Critical-Chain Buffer Calculator and replace every sample with the actual schedule, record, or system being analyzed.
- Use Project starts and Critical-chain duration days to establish the starting conditions for the Critical-Chain Buffer Calculator.
- Set Project buffer percent, Feeding chains, and Feeding buffer percent to match the actual case rather than leaving example assumptions in place.
- Run the Critical-Chain Buffer Calculator with a baseline set of values, then change only one uncertain input at a time when comparing alternatives.
Calculation
Method used
The project buffer extends the critical chain while each feeding chain receives its own percentage buffer.
The displayed formula makes the role of Project starts, Critical-chain duration days, and Project buffer percent explicit. In the Critical-Chain Buffer Calculator, keeping those inputs separate helps distinguish a changed assumption from a changed calculation rule.
Calculation method last reviewed: June 20, 2026.
Worked scenario
Example calculation
To audit your own Critical-Chain Buffer Calculator result, compare Project starts and Critical-chain duration days with the worked scenario. In the Critical-Chain Buffer Calculator, if the direction or scale looks wrong, verify Feeding buffer percent before changing several inputs at once.
Interpretation
Reviewing the generated schedule
Buffers protect delivery uncertainty and should be monitored separately from planned task duration.
Read the headline together with the supporting metrics for Project starts, Critical-chain duration days, and Project buffer percent. A plausible-looking Critical-Chain Buffer Calculator result can still be unreliable when one of those values uses the wrong unit, date boundary, or local convention.
The Critical Path Timeline Calculator extends the Critical-Chain Buffer Calculator by letting you find the longest dependent task chain and earliest project completion.
Visual audit
Reading the schedule blocks
The Critical-Chain Buffer Calculator schedule turns Project starts, Critical-chain duration days, Project buffer percent, Feeding chains, and Feeding buffer percent into ordered blocks. Within the Critical-Chain Buffer Calculator, check every transition for overlap or missing setup time, then confirm that the final block still satisfies the entered anchor or deadline.
Boundaries
Important edge cases and limitations
Resource contention, buffer-consumption rules, and dependency placement must be validated in the source plan.
If one of these exclusions applies, treat the Critical-Chain Buffer Calculator output as a baseline and correct Feeding buffer percent or another affected input before recalculating.
Practical use
Recommended workflow
Place feeding buffers at actual merge points and define how buffer consumption will trigger action.
Use the Project Slack and Float Calculator alongside the Critical-Chain Buffer Calculator to calculate total and free float from task timing and successor constraints. When work based on the Critical-Chain Buffer Calculator expands, the Reverse Project Scheduling Calculator can schedule sequential stages backward from a fixed delivery deadline.
Input audit
Checklist for this calculation
- Confirm the source and units for Project starts and Critical-chain duration days before entering them.
- Preserve Project buffer percent, Feeding chains, and Feeding buffer percent with any saved or shared Critical-Chain Buffer Calculator result.
- For the Critical-Chain Buffer Calculator, review the exclusions above for conditions that could change Feeding buffer percent or the calculation method.
- Recalculate the Critical-Chain Buffer Calculator whenever a recorded input or real-world condition changes.
Questions
Frequently asked questions
Why are feeding buffers separate from the project buffer?
They protect the critical chain from delays arriving through noncritical dependency paths.
What falls outside the scope of the critical-chain buffer calculator?
Resource contention, buffer-consumption rules, and dependency placement must be validated in the source plan.
How is the critical-chain buffer calculator result calculated?
The project buffer extends the critical chain while each feeding chain receives its own percentage buffer. Project buffer = critical-chain duration × project-buffer rate; feeding buffer = feeding-chain duration × feeding-buffer rate.
How can the worked example help check the critical-chain buffer calculator?
A sixty-day chain with a twenty-five-percent project buffer adds fifteen days after the chain, while each feeding chain receives its own buffer. Buffers protect delivery uncertainty and should be monitored separately from planned task duration.
Which conditions still need manual review after using the critical-chain buffer calculator?
Resource contention, buffer-consumption rules, and dependency placement must be validated in the source plan. Place feeding buffers at actual merge points and define how buffer consumption will trigger action.