Estimate at Completion (EAC) Calculator

Project Estimate at Completion Calculator

Estimate at Completion (EAC) Formulas

Formula

\[ EAC = AC + ETC \] \[ EAC = \frac{BAC}{CPI} \] \[ EAC = AC + (BAC - EV) \] \[ EAC = AC + \frac{(BAC - EV)}{CPI \times SPI} \]

Where:

$EAC$ — Estimate at Completion (forecasted total project cost)
$AC$ — Actual Cost (amount spent so far)
$ETC$ — Estimate to Complete (expected cost of the remaining work)
$BAC$ — Budget at Completion (original total budget)
$EV$ — Earned Value (budgeted value of the work actually performed)
$CPI$ — Cost Performance Index, $CPI = EV / AC$
$SPI$ — Schedule Performance Index, $SPI = EV / PV$
$PV$ — Planned Value (budgeted value of the work scheduled to date)

Each formula answers a different forecasting question, depending on what you believe will happen to the project for the rest of its life.

Estimate at Completion – Calculation Example

Example: a project has spent $$50{,}000$ to date. The original assumptions are no longer valid, and a fresh bottom-up estimate of the remaining work (ETC) comes to $$60{,}000$. The scenario “Original Estimate no Longer Valid” applies.

\[ EAC = AC + ETC = 50{,}000 + 60{,}000 = 110{,}000 \]

Result: EAC = $110,000 — the project is now expected to finish $10,000 over its $100,000 budget.

How to use the calculator

EAC Scenario — choose the forecasting assumption that matches your situation (see the descriptions below).
Actual Cost (AC) — enter the total cost incurred on the project so far.
Budget at Completion (BAC) — enter the original approved total budget for the project.
Earned Value (EV) — enter the budgeted value of the work completed to date.
Estimate to Complete (ETC) — enter a fresh, bottom-up estimate of the cost of the remaining work (used in scenario 1).
Planned Value (PV) — enter the budgeted value of the work that was scheduled to be complete by now (used in scenario 4).
Read the Estimate at Completion (EAC) result — the forecasted final cost of the project in your currency.

What is Estimate at Completion?

Estimate at Completion (EAC) is an earned value management (EVM) metric that forecasts the total cost of a project when it is finished. It is one of the most important numbers a project manager can produce mid-project, because it answers the question every sponsor asks: “What is this project actually going to cost us?” Unlike the original budget (BAC), which is fixed at the start, EAC is recalculated as real performance data arrives, so it reflects what the team has really spent and how efficiently it is working.

The key insight behind EAC is that past performance is often the best predictor of future performance. If a project is spending 20% more than planned for each unit of work, that overrun rarely disappears on its own — it compounds through the remaining work. EAC captures this by combining what has already been spent (AC) with a forecast of the remaining work, adjusted for the assumptions you choose.

Comparing EAC with BAC gives an immediate picture of project health: if EAC exceeds BAC, the project is forecast to overrun its budget; if EAC is below BAC, it is expected to finish under budget. The difference, $BAC - EAC$, is the Variance at Completion (VAC). Project managers use EAC trends over time — recalculated monthly, for example — to detect whether corrective actions are working.

The four EAC scenarios explained

The calculator implements the four standard EAC formulas from the PMBOK Guide. Picking the right one matters more than the arithmetic itself:

Original estimate no longer valid: $EAC = AC + ETC$. The original budget was based on flawed assumptions, so you disregard BAC and add a fresh bottom-up estimate of the remaining work to what you have already spent. This is usually the most accurate — and most time-consuming — method.
Current CPI for the rest of the project: $EAC = BAC / CPI$. The cost inefficiency observed so far is expected to continue at the same rate through completion. This is the most commonly used formula for projects that are over budget with no change expected.
Current CPI is abnormal: $EAC = AC + (BAC - EV)$. Past cost performance was caused by a one-time event (a price spike, a rework cycle) that will not repeat, so the remaining work is expected to cost exactly what was originally budgeted for it.
Project needs to meet deadline: $EAC = AC + (BAC - EV) / (CPI \times SPI)$. Both the cost and schedule overruns will persist, and the schedule must be met — typically by crashing or adding resources, which drives cost up further. This formula usually produces the highest (most pessimistic) EAC.

Assumptions, limitations and practical tips

EAC is only as good as the inputs. AC must include all committed costs, and EV must be measured with an honest progress rule (e.g. percent complete, milestones, or 50/50) — inflated progress reporting is the most common source of misleadingly optimistic EAC values.

A few practical points to keep in mind:

Scenario choice is a judgment call. If you cannot decide, calculate all applicable scenarios; the spread between the lowest and highest EAC is itself useful information for risk planning.
Scenario 2 ignores schedule. $BAC / CPI$ assumes cost performance is the only driver and that the schedule can slip freely. If the deadline is fixed and slipping, scenario 4 is more realistic.
Early data is noisy. CPI and SPI computed from the first few weeks of a project are often unstable; treat early EAC forecasts as rough indicators rather than commitments.
ETC needs real effort. In scenario 1, the quality of the answer depends entirely on the quality of your bottom-up re-estimate of the remaining work.
EAC is a cost forecast. To also evaluate whether the project is worth continuing, compare EAC against expected benefits — much like assessing the return on investment or the profitability index of an investment decision.

Recalculate EAC at every reporting period and track the trend. A steadily rising EAC is an early warning that corrective action is needed — long before the budget is actually exhausted.

Frequently Asked Questions

Which EAC formula should I use?

It depends on what you expect for the remaining work. If the original budget assumptions are invalid, use AC + ETC with a fresh bottom-up estimate. If current cost inefficiency will continue, use BAC / CPI. If past overrun was a one-time event, use AC + (BAC − EV). If the deadline is fixed and both cost and schedule overruns will persist, use AC + (BAC − EV) / (CPI × SPI). When unsure, compute several scenarios — the spread itself is useful risk information.

How do I calculate EAC by hand?

First compute your earned value metrics: $CPI = EV / AC$ and $SPI = EV / PV$. Then apply the formula for your chosen scenario. For example, with AC = $50,000, BAC = $100,000, and EV = $40,000, scenario 2 gives $CPI = 40{,}000 / 50{,}000 = 0.8$, so $EAC = 100{,}000 / 0.8 = 125{,}000$ dollars. Always double-check that EV and PV use the same progress measurement basis, otherwise the indices will be inconsistent.

What is a good or normal EAC value?

The benchmark is your BAC. An EAC at or below BAC means the project is forecast to finish on or under budget; an EAC above BAC signals an overrun. The gap $BAC - EAC$ is the Variance at Completion (VAC) — negative VAC means an expected loss against budget. There is no universal 'good' number: a healthy project simply has a stable EAC that stays close to its approved budget over successive reporting periods.

Why is my EAC higher than my budget?

Because your cost performance index is below 1: you are spending more per unit of completed work than planned. Under the CPI-based formula $EAC = BAC / CPI$, a CPI of 0.8 inflates the forecast by 25%. A high EAC may also reflect schedule pressure — scenario 4 adds the cost of accelerating work to meet the deadline. Track whether EAC rises or falls period over period; a steadily climbing EAC is an early warning to take corrective action.

How is EAC different from ETC and VAC?

ETC (Estimate to Complete) covers only the cost of the remaining work, while EAC is the total final cost: $EAC = AC + ETC$. VAC (Variance at Completion) is the difference between budget and forecast: $VAC = BAC - EAC$; a negative VAC means an overrun is expected. Another related figure is TCPI (To-Complete Performance Index), which tells you how efficiently the remaining work must be performed to still hit the BAC.

Can EAC be less than BAC?

Yes. If CPI is greater than 1 — the project is completing work cheaper than planned — then $EAC = BAC / CPI$ comes out below budget. For instance, a CPI of 1.25 on a $100,000 BAC gives an EAC of $80,000. Be cautious with optimistic forecasts, though: verify that EV is being measured honestly, because inflated progress reporting is the most common cause of unrealistically low EAC values.

What units and currencies does the calculator support?

The calculator works in any currency — enter AC, BAC, EV, ETC, and PV in the same currency and the EAC result is in that currency. The dollar sign shown is just a display symbol. Keep all inputs consistent (do not mix dollars and thousands or different currencies), and remember the formulas are pure ratios, so the result scales correctly whether you work in dollars, euros, or thousands of units.