The formulas
Everything starts from three numbers at the status date: the planned value (PV) of the work scheduled by then, the earned value (EV) of the work actually done, and the actual cost (AC) of that work. BAC is the whole budget.
| Measure | Formula | Good sign |
|---|---|---|
| Schedule variance | SV = EV − PV | Positive |
| Cost variance | CV = EV − AC | Positive |
| Schedule index | SPI = EV ÷ PV | Above 1 |
| Cost index | CPI = EV ÷ AC | Above 1 |
| Estimate at completion | BAC ÷ CPI, or AC + (BAC − EV), or AC + (BAC − EV) ÷ (CPI × SPI), or AC + bottom-up ETC | At or below BAC |
| Estimate to complete | ETC = EAC − AC | At or below BAC − EV |
| Variance at completion | VAC = BAC − EAC | Positive |
| To-complete index | TCPI (BAC) = (BAC − EV) ÷ (BAC − AC); TCPI (EAC) = (BAC − EV) ÷ (EAC − AC) | At or below CPI |
Where textbooks differ, and what this page uses
The four EACs and both TCPIs are the ones in the PMBOK Guide. TCPI comes on two bases: to finish within BAC, or to meet an approved EAC. Problems ask for each by name, using the bottom-up EAC as the approved one. Some books round CPI to two, three or four places before dividing, or work EAC as AC + (BAC − EV) ÷ CPI; here EAC uses the unrounded indices, and any EAC those routes give is marked right too. Work packages earn by percent complete × budget unless marked 0/100 or 50/50, two of the fixed-formula methods in the US government guides below. Planned value is each package’s budget spread evenly over its planned time whatever its rule, as in the DOE training example; some practitioners plan a 0/100 package’s value at its finish instead.
An example from set EXV4M2
Bridge deck repair has a BAC of $420,000 over 9 months. At the end of month 4 the chart reads PV $180,000, EV $160,000 and AC $140,000. SV = 160,000 − 180,000 = −$20,000 and SPI = 0.89: behind schedule. CV = $20,000 and CPI = 1.14: under budget. EAC = 420,000 ÷ (160,000 ÷ 140,000) = $367,500, so ETC = $227,500 and VAC = $52,500. TCPI to finish within BAC = 260,000 ÷ 280,000 = 0.93. The team’s bottom-up ETC of $299,000 gives EAC = $439,000 and TCPI (EAC) = 260,000 ÷ 299,000 = 0.87. Open set EXV4M2
Questions
What does a CPI of 0.9 mean?
Each dollar spent so far has earned 90 cents of budgeted work, so the work done cost more than planned. CPI = EV ÷ AC. SPI = EV ÷ PV reads the same way for schedule: below 1 is behind, above 1 is ahead.
How do you read PV, EV and AC from an S-curve?
Find the status date line, follow each curve to where it crosses that line, then read across to the money axis using the gridlines. Here the dashed line is PV, the line with squares is EV and the line with circles is AC.
Which EAC formula should I use?
It depends on why the project is off plan. BAC ÷ CPI if the cost trend will carry on; AC + (BAC − EV) if the variance was a one-off; AC + (BAC − EV) ÷ (CPI × SPI) if a fixed date makes both indices matter; AC + bottom-up ETC when the original estimate no longer holds.
Is TCPI worked on BAC or EAC?
Both are used. TCPI (BAC) = (BAC − EV) ÷ (BAC − AC) asks what it takes to finish on the original budget. Once a new EAC is approved, TCPI (EAC) = (BAC − EV) ÷ (EAC − AC) replaces it. This page asks for each and labels it. With EAC = BAC ÷ CPI, TCPI (EAC) always equals CPI.
Do I round CPI before working out EAC?
Textbooks differ. This page works EAC from the unrounded indices and gives it to the nearest dollar, and also marks right an EAC worked from CPI and SPI rounded to two decimal places. The key shows both when they differ.
What are the 0/100 and 50/50 rules?
Fixed-formula ways to earn value on short work packages. Under 0/100 a package earns nothing until it finishes; under 50/50 it earns half its budget when it starts and the rest at the finish. Other packages here earn by percent complete × budget.
What are BCWS, BCWP and ACWP?
The older names for PV, EV and AC, still used in US government contracts and on the DOE Gold Card: BCWS is PV, BCWP is EV and ACWP is AC. The Term names choice under Formulas changes every label on this page.
Sources, checked 2 November 2026: the DOE EVMS Gold Card (variances, indices, EAC general, CPI and composite, TCPI on EAC, VAC) and the CMS guide Earned Value Measures (0/100, 50/50 and percent complete), and DOE’s EVMS training Module 5 (planned value of a fixed-formula activity). EAC choices and TCPI bases as named in PMI’s PMBOK Guide, sixth edition, section 7.4.