Chapter 18 described the preparation of the production budget, beginning in the development phase (see Chapter 6). When funding is fully secured, a final production budget is arrived at by adjusting the then-current version so its total does not exceed the funds available. The final budget is the blueprint for expenditure on the production, a process whose description began in Chapter 5 and will continue through to Chapter 23.

The final budget anticipates a cost for every expense category in the production, but for a variety of reasons not every category will see expenditure exactly as predicted in the budget. Some categories will end up costing less than was budgeted (e.g. a discount may have become available) and that's not a problem, but some will cost more. If the additional cost over budget (called an overage) is ignored, it could create a total production cost in excess of the production's budget. If the production does not have the funding to cover this project overage, and that is likely to be the case, an invoice that comes late in the production will be unable to be paid. The budget is managed within its bottom line (the total budget figure) by identifying offsets where costs can be managed down so that the production can stay on target to come in within budget. To do this, the offsets must be timely.