What is Job Costing?

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 Allocation of Materials

In a job costing environment, materials to be used on a product or project first enter the facility and are stored in the warehouse, after which they are picked from stock and issued to a specific job. If spoilage or scrap is created, then normal amounts are charged to an overhead cost pool for later allocation, while abnormal amounts are charged directly to the cost of goods sold. Once work is completed on a job, the cost of the entire job is shifted from work-in-process inventory to finished goods inventory. Then, once the goods are sold, the cost of the asset is removed from the inventory account and shifted into the cost of goods sold, while the company also records a sale transaction.

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Job Costing Allocation of Labor

In a job costing environment, labor may be charged directly to individual jobs if the labor is directly traceable to those jobs. All other manufacturing-related labor is recorded in an overhead cost pool and is then allocated to the various open jobs. The first type of labor is called direct labor, and the second type is known as indirect labor. When a job is completed, it is then shifted into a finished goods inventory account. Then, once the goods are sold, the cost of the asset is removed from the inventory account and shifted into the cost of goods sold, while the company also records a sale transaction.

Job Costing Allocation of Overhead

In a job costing environment, non-direct costs are accumulated into one or more overhead cost pools, from which you allocate costs to open jobs based upon some measure of cost usage. The key issues when applying overhead are to consistently charge the same types of costs to overhead in all reporting periods and to consistently apply these costs to jobs. Otherwise, it can be extremely difficult for the cost accountant to explain why overhead cost allocations vary from one month to the next.

The accumulation of actual costs into overhead pools and their allocation to jobs can be a time-consuming process that interferes with closing the books on a reporting period. To speed up the process, an alternative is to allocate standard costs that are based on historical costs. These standard costs will never be exactly the same as actual costs, but can be easily calculated and allocated.

The overhead allocation process for standard costs is to use historical cost information to arrive at a standard rate per unit of activity, and then allocate this standard amount to jobs based on their units of activity. You then subtract the total amount allocated from the overhead cost pool (which contains actual overhead costs), and dispose of any remaining amount in the overhead cost pool. You can use any of the following methods to dispose of the remaining amount:

Charge to Cost of Goods Sold

Charge the entire variance to the cost of goods sold. This is the simplest method. There is no attempt to allocate the variance to more than one account.

Allocate the Variance

Allocate the variance to the accounts for finished goods, work-in-process, and cost of goods sold, based on the ending balances in these accounts. This approach is slightly more time-consuming, but is the most theoretically correct method under generally accepted accounting principles.

Charge to Jobs

Allocate the variance to those jobs that were open during the reporting period. This approach is the most time-consuming. It essentially reverts a company back to an actual costing system, since the results of this method will approximate those created under an actual cost allocation system.

The allocation of an overhead cost pool is by definition inherently inaccurate, since the underlying costs cannot be directly associated with a job. Consequently, it is best to use the simplest of the above methods to dispose of any residual amounts in the overhead cost pool.

How to Use a Job Costing System

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.

Who Uses Job Costing?

Many types of businesses can use job costing, but the inherent structure of some makes it nearly mandatory. In essence, any business that is routinely involved with unique products or projects should be avid users of job costing. A prime example is a construction company, since each building project in which it is engaged is unique. Another possibility is a consulting firm, since it must compile the costs incurred on behalf of each client. For the same reason, it makes sense for law firms to use job costing to compile costs for each client served. For both consulting and law firms, it makes sense to compile costs through a job costing system, since this makes it easier to justify billings to clients. Another obvious choice for job costing is the custom manufacturer (for example, one that constructs customized yachts), so that it can compile costs and bill them through to the client. Alternatively, if a manufacturer is operating under a fixed price arrangement, then it can use job costing to monitor its costs, thereby improving the odds of earning a profit.