Earned Value / Metrics
ACWP (Actual Cost of Work Performed)
ACWP, also called Actual Cost (AC), is what was genuinely spent to accomplish the work actually completed so far -- the real-dollar counterpart to the budgeted BCWP figure.
Definition
ACWP answers "how much did it really cost to get the work done that's actually been done." Comparing it against BCWP (the budgeted value of that same completed work) produces the Cost Variance and Cost Performance Index -- above 1.0 CPI means the work is coming in under budget relative to what was earned; below 1.0 means it's running over.
Example
$450,000 of budgeted work has been completed (BCWP), but it actually cost $420,000 to accomplish -- that $420,000 figure is the ACWP, giving a Cost Performance Index of 450,000 / 420,000 = 1.07, meaning the work came in under budget.