Actual cost, or AC, of a project is, as its name implies, the costs of delivering a project based upon the material goods that have been purchased and the costs associated with project resources. The cost of project resources is generally calculated by multiplying the hours each resource worked on a project by the hourly rate or cost of each resource. This recipe demonstrates how to calculate the actual costs of a project and its tasks using the hours each resource reported as project work and the hourly cost of those resources.