How this calculator works
Earned value management compares three money figures. Planned value is the budgeted value of the work that should be done by now. Earned value is the budgeted value of the work that actually is done. Actual cost is what has been spent. Cost variance is earned value less actual cost, and schedule variance is earned value less planned value. The cost performance index divides earned value by actual cost and the schedule performance index divides earned value by planned value. A ratio below one means over budget or behind schedule. The estimate at completion extends the current cost efficiency to the whole budget.
Formula
PV = BAC × planned progress. EV = BAC × actual progress. CV = EV - AC. SV = EV - PV. CPI = EV / AC. SPI = EV / PV. EAC = BAC / CPI (equivalently BAC × AC / EV). ETC = EAC - AC. VAC = BAC - EAC.
Worked example
On a $100,000 project, 50% planned and 40% actual progress give PV $50,000 and EV $40,000. Actual cost is $45,000, so CV is -$5,000 and SV is -$10,000. CPI is 0.8889 and SPI is 0.8. At that cost efficiency EAC is $112,500, ETC $67,500 and VAC -$12,500.
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Frequently asked questions
What do CPI and SPI below one mean?
A CPI of 0.89 means every dollar spent has earned about 89 cents of budgeted work, so the project is over budget. An SPI of 0.8 means only 80% of the planned work has been earned. Both ratios are indexed to one, not to 100.
Why use earned value instead of planned versus actual?
Because spending less than planned can mean efficiency or simply less work done. Earned value measures progress in the same money units as cost, so the two can be compared fairly.
Is a project on budget if CV is zero?
Only at this point in time and only by value of work done. The forecast at completion also depends on whether the current cost efficiency continues. If the remaining work behaves differently, EAC should be recalculated with updated estimates.