Cost of Goods Manufactured: The Complete Calculation Guide

Manufacturing vs Non-Manufacturing Businesses

Service businesses and merchandising businesses (retailers and wholesalers) have relatively straightforward cost of goods sold calculations. Service businesses have no inventory at all — their costs are period expenses. Merchandising businesses buy finished goods and resell them — cost of goods sold is simply beginning inventory plus purchases minus ending inventory.

Manufacturing businesses are different. They buy raw materials, add labour and overhead to transform those materials into finished products, and then sell the finished goods. Before you can calculate cost of goods sold for a manufacturer, you must first determine the cost of goods manufactured — the total cost of units completed during the period. This adds a layer of complexity that trips up many accounting students.

The Three Components of Manufacturing Cost

Every manufacturing cost falls into one of three categories, and understanding these categories is the foundation for everything else in this topic.

Direct materials are raw materials that are directly traceable to the finished product and represent a significant portion of its cost. Steel in an automobile, wood in furniture, and fabric in clothing are all direct materials. The key requirement is traceability — you can identify exactly how much of the material went into each unit produced.

Direct labour is the wages paid to employees who directly work on transforming raw materials into finished products — assembly workers, machine operators, and production line employees. Like direct materials, direct labour must be directly traceable to specific units of output.

Manufacturing overhead encompasses all manufacturing costs that cannot be directly traced to individual units. It includes indirect materials (lubricants, cleaning supplies), indirect labour (supervisors, maintenance workers), factory rent, factory utilities, depreciation on production equipment, property taxes on the factory, and insurance on manufacturing assets. Manufacturing overhead is allocated to units of product using a predetermined overhead rate.

The Statement of Cost of Goods Manufactured

The statement of cost of goods manufactured brings together all manufacturing costs for the period to determine the total cost of goods completed and transferred to the finished goods warehouse.

The structure of the statement is:

Direct materials used:
Beginning raw materials inventory: $XX,XXX
Add: Purchases of raw materials: $XX,XXX
Raw materials available for use: $XX,XXX
Less: Ending raw materials inventory: ($X,XXX)
Direct materials used: $XX,XXX

Plus direct labour: $XX,XXX

Plus manufacturing overhead applied: $XX,XXX

Total manufacturing costs for the period: $XXX,XXX

Plus beginning work-in-process inventory: $XX,XXX

Less ending work-in-process inventory: ($XX,XXX)

Cost of goods manufactured: $XXX,XXX

Work-in-Process Inventory

Work-in-process (WIP) inventory represents units that have been started but not yet completed at the end of the period. The cost in WIP includes the direct materials, direct labour, and manufacturing overhead that have been added to these partially completed units.

Beginning WIP is the cost of units that were started in a prior period but not completed — they carry over into the current period. Ending WIP is the cost of units started in the current period but not yet finished at period-end. The difference between beginning and ending WIP, combined with current period manufacturing costs, gives the cost of goods manufactured.

From Cost of Goods Manufactured to Cost of Goods Sold

Once cost of goods manufactured is determined, the remaining calculation is straightforward. Cost of goods sold equals:

Beginning finished goods inventory
+ Cost of goods manufactured
= Cost of goods available for sale
− Ending finished goods inventory
= Cost of goods sold

This format mirrors the cost of goods sold calculation for a merchandising business — the only difference is that "purchases" in the merchandiser's calculation is replaced by "cost of goods manufactured" in the manufacturer's calculation.

Practise these calculations with cost of goods sold practice questions and cost accounting questions on PrepQBank.

Predetermined Overhead Rates

Manufacturing overhead is applied to products using a predetermined overhead rate: budgeted overhead ÷ estimated cost driver (activity level). The cost driver is typically direct labour hours, machine hours, or direct labour cost. The predetermined rate is calculated at the beginning of the period using budgeted amounts, and is used throughout the year to apply overhead to jobs or processes as they are completed.

The difference between overhead applied and actual overhead incurred is the over- or under-applied overhead. At year-end, this difference is either closed directly to cost of goods sold (if immaterial) or allocated between work-in-process, finished goods, and cost of goods sold (if material).