Actual Cost (AC)
The real cost incurred for the work completed at a point in time.
Actual Cost (AC) is the total expenditure incurred for work performed on a project activity or work package during a specific time period. It is one of the three core Earned Value Management (EVM) inputs, alongside Planned Value (PV) and Earned Value (EV), and feeds directly into the Cost Variance (CV = EV − AC) and Cost Performance Index (CPI = EV ÷ AC) calculations used to assess cost efficiency.
The critical distinction to remember is that AC measures money spent, not work accomplished. A project can have a high AC while still being behind schedule if the earned value is lower — spending more does not mean more work is done. Exam questions often pair AC with EV to test whether candidates can correctly read a negative CV or a CPI below 1.0 as an over-budget condition rather than a schedule problem.
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