Job Order Costing Guide

A guide to job costing in accounting

What is Job Order Costing?

In managerial accounting, there are two general types of costing systems to assign costs to products or services that the company provides: “job order costing” and “process costing”. Job order costing is used in situations where the company delivers a unique or custom job for its customers. Every customer is treated differently and delivered products to specifically suit their needs.


job order costing


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Job Order Costing vs Process Costing

As an example, law firms or accounting firms would use job order costing because every client is different and unique.

Process-costing, on the other hand, is used when companies offer a more standardized product. No matter who the customer is, they all end up receiving the same product.

For example, Coca-Cola may use process costing to track its costs to produce its beverages. In job-order costing, the company tracks the direct materials, the direct labor, and the manufacturing overhead costs to determine the cost of goods manufactured (COGM).


Actual Costing (form of job order costing)

One type of job-order costing is called actual costing. The actual costing system, like the name implies, is a costing system that traces direct and indirect costs to a cost object by using the actual costs incurred in the job.

Although this system is much more simplistic, actual costing systems are not commonly found in real world situations because actual costs cannot be determined in a timely manner and are usually not known until much after the job has been completed.

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Normal Costing

Due to practical difficulties of actual costing, many companies instead utilize a normal costing system to obtain a close approximation of the costs on a timelier basis, especially manufacturing overhead costs. Direct materials and direct labor are much more feasible in terms of access to actual costs from materials requisition forms and labor time sheets while manufacturing overhead costs pose difficulties.

Due to the need for immediate access to job costs, many companies use a predetermined/budgeted a manufacturing overhead rate to estimate manufacturing overhead costs.

Commonly, predetermined rates may be that the company applies overhead costs on the basis of labor hours or machine hours. This means that the company uses labor hours or machine hours (i.e. the cost driver) to reasonably estimated for manufacturing overhead costs.

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The formula to determine this overhead rate:

Overhead rate = estimated manufacturing overhead  / estimated cost allocation base

Where the cost allocation base refers to the estimated machine hours or estimated labor hours, depending on which the company chooses to estimate its overhead costs by.


Example calculating overhead rate

XYZ Company estimates that for the current year, it would work 75,000 machine hours and incur $450,000 in manufacturing overhead costs. The company applies overhead cost on the basis of machine hours worked.

This means that the company would estimate $6 in manufacturing overhead costs for every $1 of machine hour worked. So, if the company actually worked 5000 machine hours, the estimated overhead costs would be $300,000

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The Role of Work in Process (WIP) Inventory

The WIP inventory asset account is where the actual direct materials cost used, actual direct labor cost used, and estimated manufacturing overhead costs are recorded in order to determine the COGM. This can be clearly seen through a WIP Inventory T-account.

The t-account would look like this:


Work in Process (WIP) Inventory
Beginning Balance                                               a

Direct Materials                                                    b

Direct Labor                                                          c

Manufacturing Overhead (estimated)              d

           f                                        COGM
Ending Balance                                                     e



On the credit side of the t-account is COGM. By knowing the opening and closing balances of the inventory account in addition to the actual DM and DL costs and the estimated MOH costs, the COGM can be calculated.

The estimated manufacturing overhead value can be compared to the actual manufacturing overhead value in a separate manufacturing T Account to determine any significant differences.

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Under or Over Estimated Overhead

Because the predetermined overhead rate used by companies is purely based on estimates, the actual overhead cost incurred during the year may be higher or lower than the amount estimated. This is referred to as “under or overapplied overhead.”

When overhead is underapplied, manufacturing overhead costs have been understated and upward adjustments need to be made to inventory and/or expense accounts, depending on which method the company decides to use.

In contrast, when overhead is overapplied, manufacturing overhead costs have been overstated and therefore inventories and/or expenses need to be adjusted downward. There are two ways to adjust for the under or overapplied overhead amounts.


Method 1Method 2
ProcessDifference is closed out to Cost of Goods Sold (COGS)Difference is prorated between Work in Process Inventory, Finished Goods Inventory, and COGS
FrequencyMore commonly usedRarer
Journal Entry: Situation where MOH is overapplied by $10,000DR MOH            10,000

CR Cost of Goods Sold       10,000


DR MOH        10,000

CR Cost of Goods Sold  10,000/x

CR WIP Inventory          10,000/y

CR FG Inventory            10,000/z

Value of x, y, z depends on the company


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More useful accounting guides and resources

We hope this has been a helpful guide to job order costing in accounting.  Our mission is to help you advance your career, and with that in mind we’ve created this additional resources to help you along your way: