Job costing involves the accumulation of the costs of materials, labor, and overhead for a specific job. This approach is an excellent tool for tracing specific costs to individual jobs and examining them to see if the costs can be reduced in later jobs. An alternative use is to see if any excess costs incurred can be billed to a customer.
Job costing is used to accumulate costs at a small-unit level. For example, job costing is appropriate for deriving the cost of constructing a custom machine, designing a software program, constructing a building, or manufacturing a small batch of products.
- Job costing involves the following accounting activities:
- Materials. It accumulates the cost of components and then assigns these costs to a product or project once the components are used.
- Labor. Employees charge their time to specific jobs, which are then assigned to the jobs based on the labor cost of the employees.
- Overhead. It accumulates overhead costs in cost pools, and then allocates these costs to jobs.
Job costing results in discrete “buckets” of information about each job that the cost accountant can review to see if it really should be assigned to that job. If there are many jobs currently in progress, there is a strong chance that costs will be incorrectly assigned, but the very nature of the job costing system makes it highly auditable.
If a job is expected to run for a long period of time, then the cost accountant can periodically compare the costs accumulated in the bucket for that job to its budget, and give management advance warning if costs appear to be running ahead of projections. This gives management time to either get costs under control over the remainder of the project, or possibly to approach the customer about a billing increase to cover some or all of the cost overrun.
Job costing demands a considerable amount of costing precision if costs are to be reimbursed by customers (as is the case in a cost-plus contract, where the customer pays all costs incurred, plus a profit). In such cases, the cost accountant must carefully review the costs assigned to each job before releasing it to the billing staff, which creates a customer invoice. This can cause long hours for the cost accountant at the end of a job, since the company controller will want to issue an invoice as soon as possible.