What is the Variance at Completion and what does it indicate?

The Variance at Completion, or VAC, is the difference between the original Budget at Completion and the Estimate at Completion, calculated as BAC minus EAC. A positive VAC means the project is expected to finish under budget. A negative VAC means the project is expected to exceed the budget. For example, if BAC is 200,000 dollars and EAC is 220,000 dollars, the VAC is negative 20,000 dollars, indicating the project will be 20,000 dollars over budget.