Earned Value Definitions
Estimate at Completion (EAC)

What is Estimate at Completion (EAC)? Earned Value Management explained.

Mia Rutherford
Mia Rutherford
February 24, 2024
5 min read

Estimate at Completion (EAC) is a critical financial metric in project management, offering a projection of the total cost of a project based on current performance and known factors. Understanding and forecasting EAC is essential for managing budgets, anticipating financial needs, and ensuring project success. This article delves into the nuances of EAC, exploring its definition, calculation methods, forecasting techniques, challenges, best practises, and real-world applications through case studies.

Key Takeaways

Understanding Estimate at Completion (EAC)

Definition and Importance of EAC

Estimate at Completion (EAC) is a pivotal financial metric used in project management to forecast the total cost of a project at its conclusion. It represents the expected final budget, taking into account both the work performed to date and the work remaining. The importance of EAC cannot be overstated; it serves as a crucial indicator for project managers, stakeholders, and financiers to understand the financial health and trajectory of a project.

The EAC is not a static figure; it evolves as the project progresses, reflecting changes in scope, resource allocation, and unforeseen challenges. By accurately predicting the EAC, organisations can:

For instance, Network Rail's adoption of the NEC4 framework in CP7 projects underscores the significance of flexible and efficient project management practises that aim to reduce risks and enhance user-friendliness. The ability to accurately estimate and update the EAC is integral to such frameworks, ensuring that projects like those in the rail sector can be delivered successfully within the financial parameters set out from the start.

The Relationship Between EAC and Budget at Completion (BAC)

The Estimate at Completion (EAC) and the Budget at Completion (BAC) are two pivotal financial metrics in project management. While the BAC represents the original financial blueprint for the project, the EAC is a dynamic figure that reflects the anticipated total cost by the project's end. Understanding the interplay between these two figures is crucial for effective financial control and project delivery.

It is essential to grasp that the EAC may evolve over the course of the project due to various factors such as changes in scope, unforeseen challenges, or shifts in resource availability. This fluid relationship means that the EAC can serve as an early warning system, signalling the need for corrective actions if the project's costs are veering off course from the original BAC.

Key Factors Influencing EAC

The accuracy of an Estimate at Completion (EAC) is contingent upon a multitude of factors, each playing a pivotal role in shaping the final figure. Understanding these elements is crucial for project managers to forecast costs effectively and steer their projects towards financial success.

Incorporating these factors into the EAC calculation ensures a more robust and reliable forecast. Notably, the Finding The Perfect EAC Formula For Your Project article highlights the importance of including both the cost performance index (CPI) and the schedule performance index (SPI) in the calculations, as they are expected to influence the remaining project work significantly.

Methods for Calculating Estimate at Completion

EAC with Original Budget Perspective

When considering the Estimate at Completion (EAC) from the original budget perspective, the focus is on the initial financial plan laid out for the project. This method assumes that past performance will not affect future costs, and the remaining work will be accomplished at the budgeted rate. It is a straightforward approach that relies heavily on the accuracy of the original budget.

The calculation is simple: take the original budget, or Budget at Completion (BAC), and add any actual costs incurred to date. This method is particularly useful in the early stages of a project when deviations from the budget are minimal. However, it may not be as effective when significant variances have occurred, as it does not account for changes in productivity or cost efficiency over time.

Key steps in this method include:

  1. Reviewing the original budget to ensure it is still valid.
  2. Adding the actual costs incurred to the original budget.
  3. Assessing any potential risks that may impact the remaining budget.

This approach can be beneficial for projects with a high degree of certainty and stability. It allows project managers to explore the impact of site diaries on project management, which can include tracking progress and managing resources effectively. Moreover, understanding the principles of Earned Value Management (EVM) can complement this method by providing real-time reporting and insights, which are crucial in the construction industry.

EAC with Performance Factor Consideration

When calculating the Estimate at Completion (EAC) with a focus on performance factors, it's essential to consider the project's current cost performance and extrapolate future implications. This method adjusts the original budget based on actual project performance, providing a more realistic forecast of the total project cost.

By incorporating performance factors into the EAC, project managers can identify areas where efficiency can be improved and take corrective actions. This proactive approach not only refines the accuracy of the EAC but also enhances overall project management by aligning budgetary expectations with actual performance.

EAC with Bottom-up Estimation Approach

The bottom-up estimation approach for calculating Estimate at Completion (EAC) is a meticulous process that involves re-estimating the cost of each component of the project from the ground up. This method is particularly useful when the initial assumptions of the project are no longer valid or when significant changes have occurred during the project lifecycle.

By aggregating the detailed costs of all tasks and resources, a more accurate EAC can be derived. This granular level of detail allows project managers to account for specific challenges and changes that have arisen, ensuring that the EAC reflects the current reality of the project.

The steps involved in the bottom-up estimation approach include:

  1. Reviewing the work breakdown structure (WBS) to identify all remaining tasks.
  2. Estimating the cost to complete each task, considering current data and actual performance.
  3. Summing up the individual estimates to arrive at the total EAC.

This approach is time-consuming but can provide a high level of accuracy, making it an invaluable tool for projects that have undergone significant shifts in scope or direction. It is a comprehensive guide on project cost estimation, performance analysis, and management techniques including EAC, ETC, CPI, EV, and variance analysis.

EAC Forecasting Techniques

Understanding the Role of Earned Value Management (EVM)

Earned Value Management (EVM) is a systematic project management process that integrates the three critical components of scope, schedule, and cost for optimal project performance and control. It is a cornerstone in the field of project management, providing a quantifiable approach to the assessment of project progress and its financial health.

The importance of EVM cannot be overstated; it is a tool that enables project managers to forecast the final cost and completion date with a higher degree of accuracy. This predictive capability is essential for making informed decisions and taking corrective actions when necessary, thereby safeguarding the project's success.

Forecasting EAC Using Cost Performance Index (CPI)

The Cost Performance Index (CPI) is a pivotal metric in forecasting the Estimate at Completion (EAC), providing a snapshot of the cost efficiency of the work performed to date. By comparing the budgeted cost of work performed with the actual cost incurred, CPI offers a dynamic insight into the financial health of a project.

To forecast EAC using CPI, one must follow these steps:

  1. Calculate the CPI by dividing the Earned Value (EV) by the Actual Cost (AC).
  2. Use the CPI to estimate the cost at completion by dividing the Budget at Completion (BAC) by the CPI.
  3. Adjust the forecast as necessary to account for any known project anomalies or changes.

This method assumes that what has been true for the project's cost performance will continue to be true for the duration of the project. It is particularly useful in projects where the cost variance is consistent. However, it is important to remain vigilant for any changes in project dynamics that could alter future cost performance, as these could significantly impact the EAC forecast.

Incorporating Schedule Performance Index (SPI) in EAC Forecasts

The Schedule Performance Index (SPI) is a critical metric in Earned Value Management (EVM) that measures the efficiency of time spent on a project. It is calculated by dividing the Earned Value (EV) by the Planned Value (PV). An SPI value greater than 1 indicates a project ahead of schedule, while a value less than 1 signals a delay. Incorporating SPI into EAC forecasts allows project managers to adjust their estimates to reflect not just cost performance, but also the project's schedule adherence.

When combined with the Cost Performance Index (CPI), SPI provides a more comprehensive view of the project's health. The integration of both indices into EAC forecasting involves a few key steps:

  1. Calculate the current CPI and SPI values.
  2. Determine the impact of current schedule and cost performance on the remaining work.
  3. Adjust the EAC based on the combined effect of CPI and SPI, considering any necessary corrective actions to bring the project back on track.

This dual-index approach can significantly enhance the accuracy of EAC forecasts, as it accounts for the interplay between cost and schedule, which are often tightly linked in project management. By monitoring these indices regularly, project managers can proactively identify and mitigate risks associated with cost overruns and schedule slippage.

Challenges and Best Practises in EAC Forecasting

Common Pitfalls in EAC Estimation

Estimate at Completion (EAC) is a critical metric in project management, yet it is often subject to inaccuracies due to common pitfalls. One of the most significant challenges is the reliance on inaccurate initial cost estimates. These foundational figures are crucial, as they set the baseline for all future calculations. To mitigate this risk, it is essential to:

Another frequent issue is the failure to update the EAC to reflect project changes. As projects evolve, so should the EAC, taking into account new developments and adjustments. This requires a dynamic approach to cost management and a willingness to revise estimates when necessary. Lastly, overlooking the complexity of the project or the external factors that could impact costs can lead to significant discrepancies between the EAC and the actual completion cost.

Strategies for Accurate EAC Forecasting

To enhance the precision of Estimate at Completion (EAC) forecasting, it is essential to adopt a systematic approach. Here are some strategies that can be instrumental:

By implementing these strategies, project managers can establish a robust framework for EAC forecasting, which is crucial for maintaining control over project finances and ensuring successful outcomes.

Leveraging Software Tools for EAC Calculations

In the realm of project management, the integration of software tools has revolutionised the way Estimate at Completion (EAC) calculations are performed. These tools not only streamline the process but also enhance accuracy by minimising human error.

By adopting software solutions, teams can focus on strategic decision-making rather than getting bogged down in the minutiae of calculations. For software development teams, in particular, tools like Lark provide a tailored approach to EAC, ensuring efficiency and successful project management outcomes. As the industry evolves, the use of such tools is becoming a hallmark of savvy project management practises.

Case Studies: EAC in Action

Success Stories of Accurate EAC Forecasting

The ability to forecast Estimate at Completion (EAC) with precision is a testament to a project team's expertise and the robustness of their project management systems. Accurate EAC forecasting is not just a theoretical concept but a practical reality for many successful organisations. For instance, consider the case where integrated solutions have played a pivotal role in enhancing project management efficiency and accuracy.

The success stories of accurate EAC forecasting serve as a beacon, guiding project managers towards the adoption of best practises and sophisticated tools. These narratives not only inspire but also provide a framework for others to emulate, ensuring that projects are completed within budget and on time.

Lessons Learned from EAC Forecasting Failures

The journey through project management is often paved with lessons from past experiences, particularly when it comes to financial forecasting. Failures in estimating the Estimate at Completion (EAC) can be instructive, offering valuable insights into the intricacies of project cost management.

One of the key lessons is the importance of dynamic and continuous monitoring of project variables. Relying on static data or failing to update forecasts as the project evolves can lead to significant discrepancies between the EAC and the actual completion costs.

Another lesson is the need for expertise in interpreting data and making informed decisions. Misinterpretation of cost trends or performance indices can skew the EAC, leading to either over-optimism or unnecessary contingency buffers. Ultimately, the ability to learn from these failures and implement robust EAC forecasting processes is what distinguishes successful project management practises.

The Impact of EAC on Project Management

The Estimate at Completion (EAC) is more than just a figure; it's a dynamic tool that shapes the landscape of project management. By providing a forecast of the total project cost, EAC enables managers to make informed decisions, align resources, and adjust strategies proactively. The influence of EAC on project management can be seen in several key areas:

Incorporating EAC into project management practises not only enhances the accuracy of financial forecasts but also integrates seamlessly with modern construction reporting platforms. These platforms often come equipped with features like shift planning, reporting, and fatigue management, which streamline data analysis, automate progress tracking, and facilitate effective collaboration. Trusted by many users, such tools are indispensable in today's complex project environments, where the ability to anticipate and respond to challenges is paramount.


In summary, Estimate at Completion (EAC) is a critical financial metric that provides project managers and stakeholders with a forecast of the total cost of a project at its completion. Understanding and calculating EAC allows for more informed decision-making and can help in mitigating risks associated with budget overruns. The EAC forecast is not a static figure; it evolves with the project's progress and can be recalculated using different methods depending on the project's circumstances and the data available. By integrating EAC into the project management process, organisations can ensure better financial control and increase the likelihood of delivering projects within the allocated budget. It is essential for professionals in the field to grasp the nuances of EAC and to utilise this tool effectively to steer projects towards financial success.

Frequently Asked Questions

What exactly is Estimate at Completion (EAC) in project management?

Estimate at Completion (EAC) is a forecasting tool used in project management to predict the total cost of a project at its completion. It considers the original budget, actual costs to date, and performance factors to provide a comprehensive financial projection.

How does EAC differ from Budget at Completion (BAC)?

Budget at Completion (BAC) is the original budget set for the project, whereas EAC is a dynamic estimate that reflects the actual costs incurred and the projected costs to complete the project. EAC can change as the project progresses and more information becomes available.

What are the main factors that influence the Estimate at Completion?

The main factors influencing EAC include the project's original budget, actual costs incurred, the current rate of spending, project performance, and any changes in the project scope or execution strategy.

Can you explain the Earned Value Management (EVM) technique in EAC forecasting?

Earned Value Management (EVM) is a project management technique that integrates scope, schedule, and cost variables to assess project performance and forecast EAC. It uses metrics such as Cost Performance Index (CPI) and Schedule Performance Index (SPI) to predict the final project cost.

What are some common challenges in forecasting EAC?

Common challenges in forecasting EAC include inaccurate initial estimates, changes in project scope, unforeseen events, and difficulty in measuring project performance accurately. These can lead to significant deviations from the original budget.

How can project managers improve the accuracy of EAC forecasts?

Project managers can improve EAC forecast accuracy by regularly updating estimates with actual project data, using robust EVM techniques, incorporating risk analysis, and applying lessons learned from past projects to refine the forecasting process.


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