This Basis of Estimates example shows how Alex Morgan, PMP, documented the rationale behind every cost and duration estimate for Project Phoenix — a $72,250 website launch managed using the PMBOK Guide 8th Edition. Without a solid basis of estimates, a project plan is just guesswork; this document turns estimates into defensible, auditable commitments backed by methodology and data.

What Is a Basis of Estimates?

A Basis of Estimates (BoE) is a supporting document that explains how each estimate in a project was derived. It captures the estimating techniques used, the assumptions made, the data sources referenced, and the confidence levels assigned to each figure. In PMBOK 8, the Basis of Estimates is an output of the Estimate Costs and Estimate Activity Durations processes and is an essential part of the Planning Performance Domain. It provides the evidence needed to justify budget requests, defend estimates under scrutiny, and establish a baseline against which actuals can be compared.

What's Inside This Basis of Estimates Example

This Basis of Estimates example for Project Phoenix includes:

• Estimating methodology for all 6 WBS packages: Project Management (1.1), Requirements & Design (1.2), Development (1.3), Infrastructure (1.4), Testing & QA (1.5), and Launch & Transition (1.6)
• Techniques applied per package — analogous estimating used for Project Management (based on MCG's 2022 website project), parametric estimating used for development labor (hours per feature × hourly rate), and bottom-up estimating used for Infrastructure and QA
• Confidence levels and risk adjustments: Development estimates carry a ±15% uncertainty range; Infrastructure is ±5% due to fixed vendor quotes
• Total base estimate: $62,102 with a $9,148 contingency reserve (14.7%), derived from a Monte Carlo-style range analysis
• Assumptions, constraints, and exclusions documented per package — e.g., BrightFrame's fixed-price quote ($12,900) anchored the Design package; Sam Lee and John Tran's blended rate of $65/hour drove the Development estimate

How Alex Morgan Used This Basis of Estimates

When Alex Morgan presented the $72,250 budget request to sponsor Riley Park (COO), the Basis of Estimates was the document that made the numbers credible. Rather than stating "development will cost $21,400," the BoE showed exactly how that figure was derived: 240 combined labor hours across Sam Lee and John Tran at blended rates, plus $1,000 in software licenses. Riley Park approved the budget on March 1, 2025, with no pushback — a direct result of the transparency this document provided. During execution, when CR-004 (Redis caching, +$180) was submitted, the BoE served as the reference point for confirming that the change was within the contingency reserve scope.

Download and Customize

This Basis of Estimates example is available as a free download. Use it as a reference to build your own basis of estimates, or start with the blank template and fill it in for your project.

• Download the Basis of Estimates Template — PMBOK 8 (blank, ready to use)
• Read the article: Basis of Estimates in PMBOK 8 — Guide and Best Practices

Basis of Estimates Example: Key Takeaways

The most important lesson from this Basis of Estimates example is that the document's value lies in transparency, not precision. Alex Morgan did not have perfect information at planning time — but by documenting every assumption and technique explicitly, the team could revisit and update estimates as new information emerged. When ISS-005 (hosting migration delay) occurred in Period 4, the BoE made it straightforward to isolate the cost impact and confirm it was covered by contingency. A well-written Basis of Estimates turns uncertainty into managed risk.

Want to go deeper? The PMBOK Guide 8th Edition is the definitive reference for modern project management. Get your copy and use it alongside these examples to build a solid, practical understanding of every performance domain.