How to use the earned value management calculator
- Enter the budget at completion, the planned value, the earned value and the actual cost, all in the same currency.
- Choose the forecast that matches what you expect on the remaining work: the cost trend continues, the rest goes at the budgeted rate, or both cost and schedule trends continue.
- Read the indices (CPI and SPI) and the variances to see how cost and schedule stand.
- Read the estimate at completion and the variance at completion, then check the to-complete index.
Formula
CV = EV - AC and SV = EV - PV
CPI = EV / AC and SPI = EV / PV
EAC = BAC / CPI (cost trend continues)
EAC = AC + (BAC - EV) (rest at budget) or AC + (BAC - EV) / (CPI x SPI)
TCPI = (BAC - EV) / (BAC - AC)
BAC is budget at completion, PV planned value, EV earned value and AC actual cost. ETC = EAC - AC, which equals the remaining work divided by the efficiency the forecast assumes. VAC = BAC - EAC.
A $500,000 project that is behind and over budget
The budget is $500,000. The plan called for $250,000 of work by now, $200,000 of work is done, and it cost $260,000. The cost variance is ($60,000.00) and the schedule variance is ($50,000.00). CPI is 200,000 / 260,000 = 0.7692 and SPI is 200,000 / 250,000 = 0.8. The project is 40% complete and has used 52% of its budget.
If the cost trend continues, the estimate at completion is $500,000 / 0.7692 = $650,000.00, so $390,000.00 is still to be spent and the variance at completion is ($150,000.00). If the overrun is treated as a one-off, the estimate is $260,000 + $300,000 = $560,000.00. If both trends continue it is $747,500.00. To finish on budget the remaining work would need a to-complete index of 300,000 / 240,000 = 1.25.
Why there is more than one forecast
The estimate at completion depends on a judgment about the future. If the overrun came from a problem that is fixed, assuming the rest goes to plan is reasonable. If it came from an estimate that was too low, the trend probably continues. The page shows the formula in use and lets you switch, so the assumption is visible and not hidden in the number.
The to-complete index shows the efficiency needed from now on to finish at budget, or at your forecast. A value well above 1 means the remaining work has to cost less per unit than the work so far did, which is a sign to question the plan.
Where the inputs come from
Planned value, earned value and actual cost come from a schedule and a cost record. Earned value is the budgeted cost of the work actually done, so it needs an honest measure of progress. The Critical Path Method Calculator helps with the schedule, the Three Point Estimate Calculator with uncertain tasks, and the Percentage of Completion Calculator shows a related way of measuring progress by cost.
Assumptions and limits
- All four inputs are cumulative values up to the same status date.
- Earned value cannot be more than the budget, and planned value cannot be more than the budget.
- The indices describe the project so far. No threshold is built in for what counts as good or bad.
- Taxes, risk reserves and scope changes are not modeled.
Frequently asked questions
What do CPI and SPI of 1 mean?
A cost index of 1 means each dollar spent earned a dollar of planned work, and a schedule index of 1 means the amount of work done equals the amount planned. Above 1 is better than plan and below 1 is worse.
Which estimate at completion should I use?
Use the one that matches your expectation. BAC divided by CPI assumes cost efficiency stays the same. The budget rate method assumes the past overrun will not repeat. The cost and schedule method assumes both trends continue.
What is the to-complete index?
It is the cost efficiency the remaining work must reach to finish at a target: the work still to do divided by the money still available. The page shows it for the original budget and for your forecast.
Why does the page refuse a zero actual cost?
The cost index divides by actual cost, which is not defined at zero. Enter the cost recorded so far. The schedule index likewise needs a planned value above zero.