Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Project Buffer Sizing Calculator

Estimates the project completion buffer needed using critical chain principles, factoring in task uncertainty, resource contention, and feeding chains. Use it to set realistic schedule reserves before committing to a delivery date.

Critical Chain Duration (days)

Number of Critical Tasks (tasks)

Project Uncertainty Level

Number of Feeding Chains (chains)

Resource Contention Factor

Fill in the required fields to see your result.

Project Management

Project Duration Estimator (PERT)

Estimate realistic task or project durations using the PERT three-point technique, which blends optimistic, most-likely, and pessimistic scenarios into a single weighted average. Use it whenever a single-point estimate feels too uncertain.

Optimistic Duration (days)

Most Likely Duration (days)

Pessimistic Duration (days)

Fill in the required fields to see your result.

Key differences

	Project Buffer Sizing Calculator	Project Duration Estimator (PERT)
Category	Project Management	Project Management
Inputs required	5	3
Result	Recommended Project Buffer (days)	Expected Duration (days)
What it does	Estimates the project completion buffer needed using critical chain principles, factoring in task uncertainty, resource contention, and feeding chains. Use it to set realistic schedule reserves before committing to a delivery date.	Estimate realistic task or project durations using the PERT three-point technique, which blends optimistic, most-likely, and pessimistic scenarios into a single weighted average. Use it whenever a single-point estimate feels too uncertain.