Cost Variance (CV)

The difference between a task’s estimated cost and its actual cost:

CV = BCWP - ACWP

Negative Value = over budget and/or behind schedule
Positive Value = under budget and/or ahead of schedule

Cost Performance Index (CPI)

The percentage of work completed per dollar spent

CPI = BCWP divided by ACWP

ratio > 1 = ahead of schedule and/or under budget
ratio < 1 = behind schedule and/or over budget