Earned Value Management Calculator
Measure project health in real time by calculating CPI, SPI, and the Estimate at Completion using Earned Value Management. Use it in project status reviews to forecast final cost and detect budget or schedule overruns early.
About this calculator
Earned Value Management (EVM) integrates scope, schedule, and cost into three core data points: Budget at Completion (BAC), Earned Value (EV = % complete × BAC), Planned Value (PV), and Actual Cost (AC). Key performance indicators are: Cost Performance Index CPI = EV / AC, and Schedule Performance Index SPI = EV / PV. A CPI below 1 means you are spending more than planned per unit of work. The Estimate at Completion (EAC) depends on your assumption about future performance. Using the CPI method: EAC = AC + (BAC − EV) / CPI. Using the combined CPI+SPI method: EAC = AC + (BAC − EV) / ((CPI + SPI) / 2). Using the baseline method: EAC = AC + (BAC − EV), assuming future work proceeds at the originally planned rate.
How to use
Assume BAC = $100,000, AC = $45,000, EV = $40,000, PV = $50,000, and method = CPI. Step 1 — CPI: 40,000 / 45,000 = 0.889 (over budget). Step 2 — SPI: 40,000 / 50,000 = 0.80 (behind schedule). Step 3 — EAC (CPI method): 45,000 + (100,000 − 40,000) / 0.889 = 45,000 + 67,491 ≈ $112,491. The project is forecast to overrun its $100,000 budget by about $12,500 if current cost efficiency continues. Review root causes of the CPI shortfall before accepting this forecast.
Frequently asked questions
What is the difference between CPI and SPI in Earned Value Management?
CPI (Cost Performance Index) measures how efficiently you are spending money: a CPI of 0.9 means you get $0.90 of work done for every $1.00 spent. SPI (Schedule Performance Index) measures time efficiency: an SPI of 0.9 means you are completing work at 90% of the planned rate. Both indices use 1.0 as the benchmark — values below 1 indicate problems, values above 1 indicate better-than-planned performance. Tracking both together gives a more complete picture of project health than cost alone.
Which EAC calculation method should I use for my project forecast?
The CPI method is best when past cost performance is a reliable predictor of the future, which is true for most mature, stable projects. The combined CPI+SPI method is useful when both cost and schedule inefficiencies are expected to persist, giving a more conservative estimate. The baseline method is appropriate when the root cause of current overruns has been fixed and you expect future work to proceed exactly as originally planned. PMI's PMBOK Guide recommends the CPI method as the default for most situations.
How accurate is Earned Value forecasting for long-term projects?
Research by Christensen (1999) and others has found that EVM forecasts made at the 20% completion point are typically accurate to within 10% of the final cost for defense contracts. Accuracy improves as the project progresses and more actual cost data becomes available. EVM is less reliable when the project scope is highly uncertain or when earned value percentages are estimated subjectively rather than measured objectively. Using milestone-based or binary completion rules for EV measurement significantly improves forecast accuracy.