Job costing assigns every cost (labor, material, equipment, subcontractor, overhead) to a specific job and a specific cost code within that job. The job cost report shows estimated cost versus actual cost per code, percent complete, and projected total cost at completion. It is the contractor's primary tool for managing profitability during execution. Without it, the only way to know if a job made money is at closeout, by which point it is too late to fix anything.
Good job costing depends on three habits: timecards coded to the right cost code (not just to the job), invoices coded to the right cost code on AP entry, and a weekly review of the job cost report by the project manager. QuickBooks, Sage, Foundation, ComputerEase, and most modern construction-management platforms all support job costing. The data is only as good as the coding discipline. Lazy coding ("everything to general labor") destroys the report's usefulness.