Purpose and scope
What this schedule planner builds
Add project and feeding buffers to an entered critical-chain schedule.
The Critical-Chain Buffer Calculator produces ordered blocks from Project starts, Critical-chain duration days, Project buffer percent, Feeding chains, and Feeding buffer percent; Examine Feeding buffer percent at each handoff.
Instructions
How to use this calculator
Record Project starts and Critical-chain duration days from the Critical-Chain Buffer Calculator input record, then examine Project buffer percent, Feeding chains, and Feeding buffer percent as actual constraints.
- Record Project starts and Critical-chain duration days as the Critical-Chain Buffer Calculator planning limit.
- Record Project buffer percent, Feeding chains, and Feeding buffer percent from the current input record.
- Produce the Critical-Chain Buffer Calculator blocks and examine each Feeding buffer percent transition.
- Update one uncertain Critical-Chain Buffer Calculator constraint, then contrast the revised plan.
- Compare two Feeding buffer percent values so its effect on the Critical-Chain Buffer Calculator output remains visible.
Practical use
Recommended workflow
Place feeding buffers at actual merge points and define how buffer consumption will trigger action.
When the Critical-Chain Buffer Calculator affects Feeding buffer percent, the Project Slack and Float Calculator can calculate total and free float from task timing and successor constraints. The Reverse Project Scheduling Calculator complements the Critical-Chain Buffer Calculator with a way to schedule sequential stages backward from a fixed delivery deadline.
Calculation
Method used
The project buffer extends the critical chain while each feeding chain receives its own percentage buffer.
The Critical-Chain Buffer Calculator separates Project starts, Critical-chain duration days, and Project buffer percent into stages; contrast Feeding buffer percent with the anchor before changing duration.
Calculation method last reviewed: June 21, 2026.
Worked scenario
Example calculation
Contrast the Critical-Chain Buffer Calculator stage order with Project starts and Critical-chain duration days; if spans diverge, examine Feeding buffer percent first.
Visual audit
Reading the schedule blocks
The Critical-Chain Buffer Calculator schedule produces blocks from Project starts, Critical-chain duration days, Project buffer percent, Feeding chains, and Feeding buffer percent. Examine each Feeding buffer percent handoff, then contrast Critical-Chain Buffer Calculator overlap, setup time, and deadline fit.
Boundaries
Important edge cases and limitations
Resource contention, buffer-consumption rules, and dependency placement must be validated in the source plan.
Update the affected Critical-Chain Buffer Calculator block when Feeding buffer percent is excluded, then regenerate downstream timing.
Interpretation
Reviewing the generated schedule
Buffers protect delivery uncertainty and should be monitored separately from planned task duration.
Preserve Feeding buffer percent between the first and final Critical-Chain Buffer Calculator blocks; update intermediate stages only when Feeding buffer percent from the input record allows it.
The Critical-Chain Buffer Calculator handles this calculation; the Critical Path Timeline Calculator can then find the longest dependent task chain and earliest project completion.
Input audit
Checklist for this calculation
- Examine the Critical-Chain Buffer Calculator start in Project starts and Critical-chain duration days.
- Contrast every Critical-Chain Buffer Calculator duration with the Feeding buffer percent unit.
- Examine Feeding buffer percent handoffs for gaps and setup time.
- Preserve the final Critical-Chain Buffer Calculator block inside its limit.
- Preserve Project buffer percent, Feeding chains, and Feeding buffer percent beside the Critical-Chain Buffer Calculator; include Feeding buffer percent in any saved or shared record.
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.
Can Feeding buffer percent create gaps or overlaps in the
Examine Feeding buffer percent at the limit between one Critical-Chain Buffer Calculator block and the next. Contrast the total with each Feeding buffer percent handoff before accepting the final Critical-Chain Buffer Calculator finish.
What should be saved with a critical-chain buffer calculator result?
Attach Project buffer percent, Feeding chains, and Feeding buffer percent to the saved Critical-Chain Buffer Calculator result and retain Project starts and Critical-chain duration days from the same run; units and calculation date complete the audit trail.
How often should a saved critical-chain buffer calculator result be reconsidered?
Refresh the Critical-Chain Buffer Calculator whenever the schedule source changes Project starts, Feeding buffer percent, or their relationship. Label earlier runs as historical assumptions.