Earned Value (EVM) Calculator: CPI, SPI, EAC

About the Earned Value (EVM) Calculator: CPI, SPI, EAC

Work out where a project stands with earned value management (EVM): from the budget at completion (BAC), the planned value (PV), the earned value (EV) and the actual cost (AC) you get the cost and schedule variances, the cost performance index (CPI) and schedule performance index (SPI), the estimate at completion (EAC) by three methods (and your own bottom-up estimate), the estimate to complete, the variance at completion and the to-complete performance index (TCPI). Every figure comes with one plain sentence, such as “spending 1.18 for every 1.00 of work done”.

Type the four totals, let the page add them up from % complete per task, or keep a table of reporting periods: then it also draws the S-curves of PV, EV and AC and adds the time-based earned schedule figures, SPI(t) and SV(t), with a forecast of the duration. What you type stays in this browser, so next period you only add a row. The free preview shows the CPI and a watermarked chart; every other figure, the CSV report, the chart file and the summary need a Pro pass.

The formulas

All values are cumulative to the status date, as on NASA’s integrated program management reference card:

• Cost variance CV = EV − AC, and CV % = CV ÷ EV. Schedule variance SV = EV − PV, and SV % = SV ÷ PV.
• CPI = EV ÷ AC: for every 1.00 spent, how much planned work was done. SPI = EV ÷ PV: how much of the work planned by now was done. Above 1 is favourable, below 1 unfavourable.
• Estimate at completion: EAC = AC + (BAC − EV) ÷ PF, with the performance factor PF = 1 (the rest at its budget), CPI (which gives BAC ÷ CPI) or CPI × SPI. Estimate to complete ETC = EAC − AC; variance at completion VAC = BAC − EAC.
• TCPI = (BAC − EV) ÷ (BAC − AC): the efficiency the remaining work needs to finish within the budget; with an EAC in place of BAC, to finish at that estimate.
• % planned, % complete, % spent: PV, EV and AC as shares of BAC.

Which estimate at completion?

Each method assumes something about the rest of the work:

• The rest at its budget (AC + BAC − EV) assumes the overrun so far was a one-off and the remaining work costs what was planned.
• Cost efficiency continues (BAC ÷ CPI) assumes the remaining work costs as much more (or less) than budgeted as the work so far. NASA’s card calls it “typically a best case” for a project in trouble.
• Cost and schedule efficiency continue (AC + (BAC − EV) ÷ (CPI × SPI)) also charges the schedule delay to the remaining work, “typically a worst case”.
• Your estimate to complete uses a bottom-up estimate of the remaining work instead of a formula.

Pick the one that matches what you expect, and compare its TCPI with the CPI so far: a TCPI well above the CPI means finishing at that figure needs a real change in how the work goes.

Earned schedule: schedule in time, not money

SPI and SV measure the schedule in money, so on a late project they creep back to 1.00 and 0 as earned value catches up with the budget: at the end EV = PV = BAC, however late the work is. Earned schedule (Walt Lipke) measures it in periods instead. ES is the time at which the earned value should have been earned: C whole periods whose planned value the earned value has passed, plus I = (EV − PV of period C) ÷ (PV of period C + 1 − PV of period C).

With AT, the number of periods that have passed: SPI(t) = ES ÷ AT and SV(t) = ES − AT (in periods). The forecast duration is IEAC(t) = PD ÷ SPI(t), where PD is the planned duration; if the rest goes to plan, AT + (PD − ES). Use reporting periods of the same length (weeks or months) for these figures.

Three ways to enter the status

• Four totals, when your accounts or your schedule tool already give BAC, PV, EV and AC.
• % complete per task, when you track work packages: PV = budget × planned %, EV = budget × done %, and AC is what each has cost. The totals are worked out for you.
• Reporting periods, for S-curves and earned schedule: planned value for each period of the baseline, and earned value and actual cost for each period reported so far, as running totals or as the amount of each period.

Limitations

• The figures are only as good as the earned value you type: a generous “% done” makes every index look better than the work is.
• It is a calculator, not an earned value management system: there are no control accounts, management reserve or baseline changes; type the figures of the baseline in force.
• Earned schedule assumes reporting periods of equal length and a planned value for every period of the baseline.
• One currency and no inflation or exchange-rate adjustments; amounts are shown in the currency you pick.

Privacy

Everything is worked out in your browser. The figures you type are kept in this browser on this device, so they are there next time you report, and are never uploaded. Reset deletes them.