Difficulty: Foundational | Prerequisites: None
Managerial accounting classifies every cost so the right dollar lands on the right product at the right time. Costs split into direct versus indirect (traceability), product versus period (when they hit the income statement), and variable versus fixed (how they move with volume). These classifications feed two core schedules, the Cost of Goods Manufactured and Cost of Goods Sold, which connect the factory floor to the income statement. If you can sort a cost into the right bucket and work the COGM/COGS formulas, you have the foundation for every later topic in ACC 359.
Actual cost
A cost that has already been incurred, a historical or past cost. In simple terms, it is the real amount paid for a resource that has been used up or consumed.
Direct cost
A cost that can be traced to a specific cost object (a product, department, or project) in an economically feasible way. Think of it as the cost you can point to and say, "that went into making this specific item," such as lumber in a chair.
Indirect cost
A cost related to a cost object but not traceable to it in an economically feasible way. It must be allocated using some formula or rate. In simple terms, it is a shared cost, like the plant supervisor's salary, that benefits many products but cannot be pinned to just one.
Product cost (inventoriable cost)
A cost attached to units of output, sitting on the balance sheet as inventory until the unit is sold. For a manufacturer this includes direct materials, direct labour, and manufacturing overhead (including items like plant insurance and factory rent). Think of it as a cost that "travels with the product."
Period cost
A cost expensed in the period it is incurred, regardless of whether any product is sold. Sales commissions, advertising, and administrative salaries are period costs. In simple terms, these costs are tied to time, not to production.
Variable cost
A cost that changes in total in direct proportion to changes in activity level. Per unit, it stays constant. Think of direct materials: double the output, double the material spend.
Fixed cost
A cost that stays the same in total across a relevant range of activity. Per unit, it drops as volume rises. Factory rent is the classic example.
Step-fixed cost
A cost that holds constant over a narrow range of activity, then jumps to a new level. On a graph it looks like a staircase. A common example is hiring one technician for every 150 patients: the salary is flat until patient count crosses the threshold, then it steps up.
Mixed cost (semi-variable cost)
A cost with both a fixed component and a variable component. A mobile phone plan with a flat monthly fee plus per-minute charges is a mixed cost.
High-low method
A technique for splitting a mixed cost into its fixed and variable parts using only the data points at the highest and lowest activity levels (not the highest and lowest costs). Variable cost per unit = (Cost at high activity minus Cost at low activity) / (High activity minus Low activity).
Matching principle
The accounting rule that expenses should be recognised in the same period as the revenues they help generate. Product costs sit in inventory until sale, then appear as COGS in the period the revenue is recorded. Period costs hit the income statement immediately because they are tied to time rather than to specific units of output.
Cost of Goods Manufactured (COGM)
The total production cost of units finished during the period. Calculated as Total Manufacturing Costs + Beginning WIP minus Ending WIP.
Cost of Goods Sold (COGS)
The cost of the units that were sold during the period. Calculated as Beginning Finished Goods + COGM minus Ending Finished Goods.
Direct costs can be physically or conveniently traced to a cost object. Examples: raw wood going into a specific table, wages of the worker assembling that table.
Indirect costs benefit multiple cost objects and must be allocated. Examples: factory rent, plant insurance, the salary of a supervisor who oversees several product lines.
The distinction depends on the cost object chosen. A cost that is direct to a department may be indirect to a single product within that department.
Product costs (inventoriable costs) attach to units and sit on the balance sheet as inventory until the unit is sold. For a manufacturer, the three categories are:
Direct materials
Direct labour
Manufacturing overhead (all indirect manufacturing costs, including plant insurance, factory utilities, factory depreciation)
Period costs are expensed immediately in the period incurred. They include:
Selling costs (sales commissions, advertising)
Administrative costs (executive salaries, office rent)
The matching principle drives this split. Product costs match against revenue in the period of sale. Period costs match against the time period in which they occur.
Misclassifying a product cost as a period cost (or vice versa) misstates both inventory on the balance sheet and net income on the income statement.
For a manufacturer, anything incurred inside the factory to make the product is inventoriable. Plant insurance is manufacturing overhead and therefore inventoriable. Sales commissions, advertising, and administrative salaries are period costs and are never inventoried.
Total variable cost rises and falls in direct proportion to activity.
Variable cost per unit stays constant.
On a graph of total cost vs activity, variable costs form a straight line through the origin.
Total fixed cost does not change within the relevant range.
Fixed cost per unit drops as volume increases (spreading effect).
On a graph, total fixed cost is a flat horizontal line.
Constant over a small range of activity, then jumps to a higher level.
On a graph, the pattern looks like a staircase: a series of horizontal segments at increasing heights.
Example: one technician hired per 150 patients. If patient count goes from 150 to 151, a second technician is needed and the salary cost steps up.
Contain both a fixed element and a variable element.
Total cost = Fixed component + (Variable rate per unit x Activity level).
On a graph, a mixed cost is a straight line that does not pass through the origin because of the fixed base.
Used to separate a mixed cost into its fixed and variable parts when you only have two usable data points.
Identify the periods with the highest and lowest activity levels (not the highest and lowest costs).
Variable cost per unit = (Cost at high activity minus Cost at low activity) / (High activity minus Low activity).
Fixed cost = Total cost at either point minus (Variable cost per unit x Activity at that point).
Cost equation: Y = Fixed cost + (Variable cost per unit x X).
Worked example from the practice exam:
High: 400 hours, $5,000
Low: 150 hours, $2,500
Variable cost per hour = ($5,000 minus $2,500) / (400 minus 150) = $2,500 / 250 = $10/hour
Fixed cost = $5,000 minus ($10 x 400) = $5,000 minus $4,000 = $1,000
Cost equation: Y = $1,000 + $10X
Estimated cost at 300 hours = $1,000 + ($10 x 300) = $4,000
Manufacturing costs flow through three inventory accounts before reaching the income statement:
Raw Materials Inventory (materials purchased but not yet used)
Work in Process Inventory (units started but not yet finished)
Finished Goods Inventory (completed units awaiting sale)
When units are sold, their cost leaves Finished Goods and appears on the income statement as Cost of Goods Sold.
COGM answers: what did it cost to finish all units completed this period?
Total Manufacturing Costs = Direct Materials Used + Direct Labour + Manufacturing Overhead
COGM = Total Manufacturing Costs + Beginning WIP minus Ending WIP
If Ending WIP is larger than Beginning WIP, some costs stayed on the factory floor (more work was started than finished), so COGM is less than Total Manufacturing Costs.
Worked example:
Direct materials used: $140,000
Direct labour: $100,000
Manufacturing overhead: $200,000
Beginning WIP: $30,000
Ending WIP: $50,000
Total Manufacturing Costs = $140,000 + $100,000 + $200,000 = $440,000
COGM = $440,000 + $30,000 minus $50,000 = $420,000
COGS answers: what cost left the building with the units customers bought?
COGS = Beginning Finished Goods + COGM minus Ending Finished Goods
If Ending FG is smaller than Beginning FG, the company sold more than it produced (drew down inventory), pushing COGS above COGM.
Worked example (continued):
Beginning Finished Goods: $80,000
COGM: $420,000
Ending Finished Goods: $60,000
COGS = $80,000 + $420,000 minus $60,000 = $440,000
\text{Total Manufacturing Costs} = \text{DM} + \text{DL} + \text{MOH}\text{COGM} = \text{Total Mfg Costs} + \text{Beg WIP} - \text{End WIP}\text{COGS} = \text{Beg FG} + \text{COGM} - \text{End FG}\text{Variable cost per unit (High-Low)} = \frac{\text{Cost}_{\text{high}} - \text{Cost}_{\text{low}}}{\text{Activity}_{\text{high}} - \text{Activity}_{\text{low}}}\text{Fixed cost} = \text{Total cost at high point} - (\text{Variable cost per unit} \times \text{Activity at high point})\text{Total cost equation: } Y = F + vXStudents often confuse actual costs with budgeted or standard costs. A budgeted figure is a forecast. An actual cost is what was spent. The average of several past periods is a historical average, not an actual cost of the current period.
Students often think the high-low method picks the months with the highest and lowest costs. It picks the highest and lowest activity levels, then reads off the costs at those points. This distinction appears on exams.
Students sometimes classify plant insurance or factory depreciation as period costs because they do not physically become part of the product. They are manufacturing overhead and therefore inventoriable.
Students forget the direction of the WIP adjustment in the COGM formula. If Ending WIP exceeds Beginning WIP, you subtract the net increase because those costs have not yet left the factory.
The COGM and COGS schedules appear in nearly every managerial accounting exam. Know the formulas cold and practise plugging in numbers quickly.
Expect at least one question that tests whether you can distinguish an inventoriable cost from a period cost. The trick is to ask: does this cost originate on the factory floor? If yes, it is inventoriable.
The high-low method is a reliable short-answer or calculation question. Remember: activity levels choose the data points, then you solve for variable cost per unit first and fixed cost second.
The matching principle is frequently tested conceptually. Be ready to explain why product costs sit in inventory and only hit the income statement when the unit is sold.
Step-fixed costs are a popular multiple-choice distractor. If a question describes a "staircase" pattern on a cost-volume graph, the answer is step-fixed, not mixed and not strictly fixed.
True or False: Sales commissions are an inventoriable cost for a manufacturer.
False. Sales commissions are a selling expense (period cost).
Fill in the blank: COGM = Total Manufacturing Costs + ______ minus ______.
Beginning WIP; Ending WIP.
True or False: The high-low method selects data points based on the months with the highest and lowest total costs.
False. It selects based on the highest and lowest activity levels.
Fill in the blank: A cost that stays constant in total over a narrow range and then jumps is called a ______ cost.
Step-fixed cost.
True or False: Plant insurance is a period cost because it does not physically become part of the product.
False. Plant insurance is manufacturing overhead and is inventoriable.
Q: Which of the following is an actual cost of the current period: (a) budgeted material cost, (b) expected cost from engineering specs, (c) cost of materials in a finished chair ready for shipment, (d) average of historical cost data?
A: (c). An actual cost is a cost already incurred. The other options describe budgeted, estimated, or averaged figures.
Q: A company's data shows Direct Materials Used $140,000, Direct Labour $100,000, Manufacturing Overhead $200,000, Beginning WIP $30,000, Ending WIP $50,000. What is COGM?
A: Total Manufacturing Costs = $440,000. COGM = $440,000 + $30,000 minus $50,000 = $420,000.
Q: Using the COGM from above, Beginning Finished Goods of $80,000, and Ending Finished Goods of $60,000, what is COGS?
A: COGS = $80,000 + $420,000 minus $60,000 = $440,000.
Q: Maintenance data shows 400 hours/$5,000 (high) and 150 hours/$2,500 (low). Estimate total cost at 300 hours using the high-low method.
A: Variable cost = ($5,000 minus $2,500) / (400 minus 150) = $10/hour. Fixed cost = $5,000 minus ($10 x 400) = $1,000. At 300 hours: $1,000 + ($10 x 300) = $4,000.
Q: Define direct cost and indirect cost in relation to a product.
A: A direct cost can be traced to a specific product in an economically feasible way (e.g. lumber for a chair). An indirect cost is related to the product but cannot be traced economically and must be allocated (e.g. plant supervisor salary).
The product-vs-period distinction feeds directly into absorption costing vs variable costing (Doc 2): under absorption costing, fixed manufacturing overhead is a product cost; under variable costing, it is treated as a period cost. Understanding that difference starts here.
The COGM and COGS schedules connect to budgeting (Doc 2): the production budget, direct materials budget, and manufacturing overhead budget all feed the numbers that eventually land in these schedules.
Cost behaviour classification (variable, fixed, step-fixed, mixed) is the foundation for cost-volume-profit analysis (Doc 2), where you need to know which costs change with volume and which do not.
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