Contract costing is a method of accounting for construction or manufacturing projects that take longer than one accounting period to complete. It involves opening a separate account for each contract to track direct costs like materials, labor, and overhead. As work is completed and certified, the contract account is credited for the corresponding portion of the contract price to calculate the profit or loss on that portion. For incomplete contracts at the end of an accounting period, only a portion of the estimated total profit is recognized depending on how much of the work has been certified complete. This method aims to match revenues and expenses across accounting periods for long-term contracts.