Redwood Works, Inc. ships 1,000 custom fixtures in a month at $150 each, and management is trying to answer two questions that affect real decisions. First, how much of the month’s spending is tied to making the product, versus selling and running the business. Second, how much cost changes with volume, versus stays fixed even if volume drops. Those two cuts drive pricing conversations, capacity decisions, and which costs are relevant in a short term choice.
The starting point is to group Redwood’s monthly costs by what they support. Direct materials are $45,000, direct labor is $30,000, variable manufacturing overhead is $18,000, fixed manufacturing overhead is $42,000, variable selling and administrative is $10,000, and fixed selling and administrative is $25,000. Before we name any formal buckets, make one prediction. Which two line items are added to get conversion cost for the month.
Conversion cost is the cost of turning materials into finished goods, so it includes Direct Labor plus all Manufacturing Overhead. Redwood’s conversion cost for the month is $30,000 plus ($18,000 + $42,000) which equals $90,000, and that is the pool managers watch for labor efficiency, overtime, maintenance patterns, and overhead control. Product cost for the month adds Direct Materials, so Redwood’s total product cost is $45,000 + $90,000 = $135,000, while selling and administrative costs stay outside product cost at $10,000 + $25,000 = $35,000.
A cost label has to answer three tests that come up in internal reporting and external reporting. First is traceable versus indirect, meaning whether we can link the cost to one cost object such as a job, product, or department without an arbitrary allocation. Second is product versus period, meaning whether the cost is part of manufacturing the product or is a cost of the time period like selling and office functions. Third is inventoriable versus expensed, meaning whether the cost is included in inventory until the goods are sold, or recognized immediately in the period incurred. Under ASC 330, product costs that are inventoriable include direct materials, direct labor, and manufacturing overhead, while selling and administrative are period costs expensed as incurred.
Now apply those tests to Redwood items that a supervisor actually sees on a monthly spend report. Steel used in the fixtures is direct material and inventoriable. Assemblers’ wages are direct labor and inventoriable. A shop supervisor’s salary is not traceable to a single unit or job in a cost effective way, so it is manufacturing overhead and inventoriable. Plant rent and plant depreciation support the factory as a whole, so they are fixed manufacturing overhead and inventoriable. Sales commissions vary with sales volume, but they are selling cost, so they are period cost expensed as incurred. Office salaries are fixed selling and administrative, also period cost expensed as incurred. Put each item into the bucket you would use in a job cost sheet or manufacturing income statement.