Budget Overrun Calculator: CPI, EAC, VAC, and TCPI
Free Earned Value Management calculator. Enter your project figures to calculate all primary EVM metrics and get an immediate RAG status assessment.
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Required Inputs
EAC Method + Optional
CPI Interpretation Guide
| CPI Range | Meaning | Recovery Likelihood | Recommended Action |
|---|---|---|---|
| CPI > 1.1 | Under budget, delivering more value per dollar than planned | N/A: already ahead | Maintain; consider whether estimates need revision |
| CPI 0.95-1.1 | On track: normal performance band | High: maintain | Normal management; monthly review |
| CPI 0.8-0.95 | Minor overrun developing | Medium: corrective action needed | Identify cost drivers; scope review; increase reporting frequency |
| CPI 0.6-0.8 | Significant overrun: project in trouble | Low: major intervention needed | Escalate to sponsor; scope reduction; reforecast budget |
| CPI < 0.6 | Severe overrun: project in jeopardy | Very low: consider project reset | Executive escalation; potential termination or full reset |
The bands above are our working thresholds. The research behind them: Christensen and Heise (1993) studied 155 US Department of Defense contracts and found the cumulative CPI stable (a range under 0.2) from the 20% completion point for 134 of the 155, usually getting worse rather than better as work continued (Cost Performance Index Stability, National Contract Management Journal, read 8 October 2026).
EVM Formula Reference
Positive = under budget. Negative = over budget. Dollar amount of variance.
Positive = ahead of schedule. Negative = behind schedule. Dollar amount of schedule variance.
For every $1 spent, you are delivering $[CPI] of planned value. CPI < 1 = over budget.
For every $1 of planned progress, you have completed $[SPI] of work. SPI < 1 = behind schedule.
Assumes current cost efficiency will continue for the rest of the project. Most common.
Optimistic: assumes remaining work will be done exactly on budget.
Projected surplus (positive) or overrun (negative) at project completion.
The CPI that must be achieved on all remaining work to finish on budget. TCPI > 1.2 is generally unachievable.
Frequently Asked Questions
What does a CPI of less than 1 mean?
CPI (Cost Performance Index) = Earned Value / Actual Cost. A CPI less than 1.0 means you are getting less than $1 of value for every $1 spent. CPI of 0.85 means: for every $1 spent, you have delivered $0.85 of planned work. PMI research shows that projects with CPI below 0.9 rarely recover significantly.
What is TCPI and what does a TCPI above 1 mean?
TCPI (To-Complete Performance Index) = (BAC - EV) / (BAC - AC). It answers: what CPI must we achieve on all remaining work to finish on budget? TCPI of 1.0 means remaining work must be done exactly on budget. TCPI of 1.1 means 10% more efficient than planned. TCPI above 1.2 is generally considered unachievable without a budget change.
What are the methods for calculating EAC?
The three primary EAC methods: (1) EAC = BAC / CPI: assumes current efficiency continues (most common); (2) EAC = AC + (BAC - EV): optimistic, assumes remaining work on budget; (3) EAC = AC + ETC: uses a new bottom-up estimate for remaining work (most accurate when circumstances have fundamentally changed). PMBOK 7 also defines EAC = AC + [(BAC - EV) / (CPI x SPI)].
What is BAC in EVM?
Budget at Completion (BAC) is the total authorized budget for a project, the planned cost of all work. It is the baseline against which all EVM metrics are calculated. BAC is set at project start and should not change unless formally re-baselined through a change control process.