第二章
成本概念和成本分类
学习目标
掌握生产成本的三大项目并举例
区别产品成本和期间成本并举例
了解完工产品成本计算表
掌握变动成本和固定成本的区别
掌握直接成本和间接成本的区别
掌握决策成本类型：差量成本、机会成本、沉没成本
成本概念
未耗成本
代表未来的经济利益，在资产负债表上列为资产，如材料成本、商品存货成本及厂场设备成本等。
成本（cost）是指经济活动中为实现特定目标或进行某种活动所耗费或放弃的资源的货币计量。
已耗成本（费用expense）
是现行会计期内为赚取当期收益而作出的牺牲，在收益表上列为费用，如商品销售成本、折旧费等。
成本的分类
从四方面目的分类：
编制财务报告（Financial reporting）
制造成本和非制造成本（期间成本）
预计成本性态（Predicting cost behavior）
变动成本和固定成本
分配成本到成本对象（Assigning costs to cost objects）
直接成本和间接成本
经营决策（Decision making）
差量成本、机会成本、沉没成本
制造成本（Manufacturing Costs）
产 品
直接材料
直接人工
制造费用
直接材料（Direct Materials）
构成产品实体的所有耗用的原材料（Raw materials），可以方便地直接追溯至产品 。
例如：安装到汽车上的音响、轮胎
直接人工（Direct Labor）
直接从事产品生产的雇员工资，可以容易地直接追溯至每一个单位产品。
例如：支付给汽车组装工人的工资
制造费用（Manufacturing Overhead）
也称工厂间接费用，指除直接材料和直接人工以外的所有制造成本。不能直接追溯到每个特定产品上。
例如：间接（indirect）人工和间接材料
支付给不直接从事产品生产工作的雇员工资。 例如：维修工人，保安人员，工厂管理人员的工资
用于支持生产过程所耗用的材料。
例如：机器设备用的润滑剂，生产车间用的清洁材料
制造成本的其他划分
制造成本通常还可划分如下：
直接材料
直接人工
制造费用
主要成本Prime Cost
加工成本Conversion Cost
非制造成本（Non-manufacturing Costs）
推销或销售成本 Marketing or Selling Cost
为获得订单和交付产品所发生的必要支出。
行政管理成本
Administrative Cost
所有高级行政管理人员薪金组织机构的办公费等。
产品成本和期间成本
产品成本（Product costs）包括直接材料、直接人工和制造费用。
期间成本（Period costs） 包括销售费用和行政管理费用。
存 货
销 货 成 本
资产负债表
收益表
销售
费 用
收益表
练习
在制造企业，下列成本中的哪些项目应作为期间成本而不是产品成本?
A. 机器设备的折旧费
B. 公司总部的财产税
C. 直接材料成本
D. 生产设施照明用电成本
E. 销售佣金
商业活动和制造活动的区别
商业企业 . . .
购入商品
销售商品
制造企业 . . .
购买原材料
生产产品
销售产成品
MegaLoMart
资产负债表
商业企业
流动资产
现金
应收款项
预付费用
商品存货
制造企业
流动资产
现金
应收款项
预付费用
存货
原材料
在制品（Work in Process）
产成品（Finished Goods）
资产负债表
商业企业
流动资产
现金
应收款项
预付费用
商品存货
制造企业
流动资产
现金
应收款项
预付费用
存货
原材料
在制品
产成品
部分完工的产品－已投入部分材料、人工和制造费用。
等待投入生产的材料
全部完工准备销售
收益表
制造企业的销货成本（Cost of goods sold）与商业企业的销货成本稍有不同。
存货流转
期初余额
本期增加
+
可供销售
（或使用）
=
期末余额
=
销售
（或转出）
_
可供销售
（或使用）
练习
如果月初存货余额为$1 000，当月购入$100，当月销售$300，问当月期末余额是多少?
A. $1 000
B. $ 800
C. $1 200
D. $ 200
完工产品成本计算表
计算生产耗用（当期发生的）的原材料、直接人工和制造费用。
计算当期生产完工的产成品的制造成本。
产品成本的流转
将原材料存货转出，投入到生产过程，所耗用的原材料就称为“直接材料”。
产品成本的流转
加工成本是指将直接材料加工成产成品所发生的成本。
三者相加得出当期制造总成本
产品成本的流转
将当期发生的制造总成本与期初在制品余额相加，得出当期在制品总成本。
产品成本的流转
从当期在制品总成本中减去期末在制品成本，得出当期完工产品成本。将当期完工产品成本转入产成品存货账户。
产品成本的流转
制造成本的流转
产成品
销货
成本
销售和管理费用
期间成本
销售和管理费用
制造费用
在制品
直接人工
成本 资产负债表
收益表
费用
购入材料
原材料
练习
期初原材料存货为$32 000，当月购入原材料$276 000，月末盘点显示结存原材料 $28 000。问当月直接材料成本是多少?
A. $276 000
B. $272 000
C. $280 000
D. $ 2 000
练习
当月生产耗用的直接材料总计$280 000，直接人工为$375 000，工厂间接费用为$180 000。问当月发生的制造总成本是多少?
A. $555 000
B. $835 000
C. $655 000
D. 不能确定
练习
期初在制品存货为$125 000，本月发生制造成本$835,000，月末尚有$200,000在制品没有完工。问当月完工产品成本是多少?
A. $1 160 000
B. $ 910 000
C. $ 760 000
D. 不能确定
练习
期初产成品存货为$130 000，当月完工产品成本为$760 000，月末产成品存货为$150 000。问当月销货成本是多少?
A. $ 20 000
B. $740 000
C. $780 000
D. $760 000
按成本性态（Cost Behavior）分类
成本性态是指成本总额与业务量之间的依存关系。分为变动成本和固定成本
变动成本（variable cost）总额随业务量的变动成正比例变动。
当业务量变动时，固定成本（fixed costs）总额保持不变。
变动成本总额
长途电话费账单随打电话的时间而增加。
通话时间（分钟）
长途电话费总额
单位变动成本
长途电话每分钟话费保持不变。例如每分钟10美分。
通话时间
每分钟话费
固定成本总额
本地话费不论打多少每月固定不变（美国）。
固定月租费不变（我国）。
当地通话时间
每月基本话费
单位固定成本
平均每分钟固定话费随通话时间增加而降低。
当地通话时间
每分钟基本话费
按成本性态分类
练习
下面哪些成本是与BR商店销售冰淇淋蛋卷数量有关的变动成本?
A. 商店照明成本
B. 商店管理人员薪金
C. 冰淇淋成本
D. 为顾客提供的餐巾纸成本
按对成本对象的可追溯性分类
成本对象（Cost objects） 是指需要单独计算成本的任何项目。
例如：一个产品
一项服务
一项活动
某个顾客
内部单位
分为直接成本和间接成本
按对成本对象的可追溯性分类
直接成本（Direct costs）
可以容易、方便地直接追溯到某个产品或其他成本对象上的成本。
例如：直接材料和直接人工
间接成本（Indirect costs）
不能直接追溯到某个产品或其他成本对象上的成本（共同成本）。
例如：间接制造费用
按决策目的进行成本分类
每项决策都涉及在至少两个方案之间进行选择。
只有不同方案之间具有差别的成本或收益才与决策相关。除此之外，所有的其他成本和收益都应该排除。
差量成本和差量收入
不同方案之间具有差别的成本或收入就是差量成本或差量收入（Differential Costs and Revenues）
例如：你在本市有一份每月收入$1 500的工作，在相邻的城市你也可以获得一份月收入$2 000的工作，城市间往返的费用是每月$300。
差量收入是：
$2,000 – $1,500 = $500
差量成本是：
$300
机会成本（Opportunity Costs）
选择一个方案而放弃另一个方案的潜在收益。
例如：如果你没有上大学，每年可挣得$15 000，你上大学的机会成本就是每年$15 000。
沉没成本（Sunk Costs）
指已经发生，不能被现在和将来的任何决策所改变的成本。它们不应该在决策时考虑。
例如：你两年前花 $10 000买了一辆汽车。这$10 000成本就是沉没成本。 不论你开车、停车、将其交换或销售，你都不会改变这$10 000成本。
第二章结束
Managers need to rely upon different classifications of costs for different purposes. The four main purposes emphasized in this chapter include preparing external financial reports, predicting cost behavior, assigning costs to cost objects, and making business decisions. Our initial focus is on manufacturing companies since their basic activities include most of the activities found in other types of business organizations. Nonetheless, many of the concepts developed in this chapter apply to diverse organizations.
Manufacturing costs are usually grouped into three main categories: direct materials, direct labor, and manufacturing overhead. These costs are incurred to make a product.
Direct materials are raw materials that become an integral part of the finished product and that can be physically and conveniently traced to it.
Examples include the aircraft engines on a Boeing 777, the Intel processing chip in a personal computer, the blank video cassette in a pre-recorded video, and a radio in an automobile.
Direct labor consists of that portion of labor cost that can be easily traced to a product. Direct labor is sometimes referred to as “touch labor” since it consists of the costs of workers who “touch” the product as it is being made.
Manufacturing overhead consists of all manufacturing costs other than direct materials and direct labor. These costs cannot be easily and conveniently traced to products. These costs are also called indirect manufacturing cost, factory overhead, and factory burden. Examples include miscellaneous supplies such as rivets in a Boeing 777; salaries for supervisors, janitors, and security guards; factory facility charges, etc.
Prime cost consists of direct materials plus direct labor. Conversion cost consists of direct labor plus manufacturing overhead.
A manufacturing company incurs many other costs in addition to manufacturing costs. For financial reporting purposes most of these other costs are typically classified as marketing or selling costs and administrative costs. These costs are also called selling, general and administrative costs, or S, G, and A. Marketing and administrative costs are incurred in both manufacturing and merchandising firms.
Marketing costs include all costs necessary to secure customer orders and get the finished product into the hands of the customer. These costs are also referred to as order-getting and order-filling costs.
Administrative costs include all executive, organizational, and clerical costs associated with the general management of an organization that are not classified as production or marketing costs.
Costs can also be classified as period or product costs.
Product costs include all the costs that are involved in acquiring or making a product. More specifically, it includes direct materials, direct labor, and manufacturing overhead. Consistent with the matching principle product costs are recognized as expenses when the products are sold. This can result in a delay of one or more periods between the time in which the cost is incurred and when it appears as an expense on the income statement. Product costs are also known as inventoriable costs. The discussion in the chapter follows the usual interpretation of GAAP in which all manufacturing costs are treated as product costs.
Period costs include all marketing or selling costs and administrative costs. These costs are expensed on the income statement in the period incurred. All selling and administrative costs are typically considered to be period costs. The usual rules of accrual accounting apply to period costs. For example, administrative salary costs are “incurred” when they are earned by the employees and not necessarily when they are paid to employees.
Which of the following costs would be considered a period rather than a product cost in a manufacturing company?
Merchandising companies purchase finished goods from suppliers for resale to customers. Manufacturing companies purchase raw materials from suppliers and produce and sell finished goods to customers.
Now, let’s consider similarities and differences on the balance sheet for merchandising and manufacturing companies. Both merchandising and manufacturing companies will likely have Cash, Receivables and Prepaid Expenses. However, merchandising companies do not have to distinguish between raw materials, work in process, and finished goods. They report one inventory number on their balance sheet labeled merchandise inventory. Manufacturing companies report three types of inventory on their balance sheets: raw materials, work in process and finished goods.
Merchandising companies calculate cost of goods sold as Beginning Merchandise Inventory plus Purchases minus Ending Merchandise Inventory.
For manufacturing companies, the cost of goods sold for a period is not simply the manufacturing costs incurred during the period. Some of the cost of goods sold may be for units completed in a previous period. And some of the units completed in the current period may not have been sold and will still be on the balance sheet as assets. The cost of goods sold is computed with the aid of a schedule of costs of goods manufactured, which takes into account changes in inventories. The schedule of cost of goods manufactured is not ordinarily included in external financial reports, but must be compiled by accountants within the company in order to arrive at the cost of goods sold. We will learn more about a schedule of costs of goods manufactured later in this chapter. Manufacturing companies calculate cost of goods sold as Beginning Finished Goods Inventory plus Cost of Goods Manufactured minus Ending Finished Goods Inventory.
Before proceeding, it is a good idea to understand that the raw materials, work in process, and finished goods inventories all follow the same logic. They start out with some beginning inventory. Additions are made during the period. At the end of the period, everything that started in the inventory or that was added must either be in the ending inventory or have been transferred out to another inventory account or to cost of goods sold.
If your inventory balance at the beginning of the month was one thousand dollars, you bought one hundred dollars during the month, and sold three hundred dollars during the month, what would be the balance at the end of the month?
The schedule of cost of goods manufactured contains the three elements of costs mentioned previously, namely direct materials, direct labor, and manufacturing overhead. It calculates the cost of raw material, direct labor and manufacturing overhead used in production. It also calculates the manufacturing costs associated with goods that were finished during the period.
To create a schedule of cost of goods manufactured as well as a balance sheet and income statement, it is important to understand the flow of product costs. Raw material purchases made during the period are added to beginning raw materials inventory. The ending raw materials inventory is deducted to arrive at the raw materials used in production. As items are removed from the raw materials inventory and placed into the production process, they are called direct materials.
Direct labor and manufacturing overhead (also called conversion costs) used in production are added to direct materials to arrive at total manufacturing costs.
Total manufacturing costs are added to the beginning work in process to arrive at total work in process.
The ending work in process inventory is deducted from the total work in process for the period to arrive at the cost of goods manufactured.
The cost of goods manufactured is added to the beginning finished goods inventory to arrive at cost of goods available for sale. The ending finished goods inventory is deducted from this figure to arrive at cost of goods sold.
Part I
All raw materials, work in process, and unsold finished goods at the end of the period are shown as inventoriable costs in the asset section of the balance sheet.
Part II
As finished goods are sold, their costs are transferred to cost of goods sold on the income statement.
Part III
Selling and administrative expenses are not involved in making the product; therefore, they are treated as period costs and reported on the income statement for the period the cost is incurred.
Beginning raw materials inventory was thirty two thousand dollars. During the month, two hundred seventy six thousand dollars of raw material was purchased. A count at the end of the month revealed that twenty eight thousand dollars of raw material was still present. What is the cost of direct material used?
Direct materials used in production totaled two hundred eighty thousand dollars. Direct labor was three hundred seventy five thousand dollars and factory overhead was one hundred eighty thousand dollars. What were total manufacturing costs incurred for the month?
Beginning work in process was one hundred twenty five thousand dollars. Manufacturing costs incurred for the month were eight hundred thirty five thousand dollars. There were two hundred thousand dollars of partially finished goods remaining in work in process inventory at the end of the month. What was the cost of goods manufactured during the month?
Beginning finished goods inventory was one hundred thirty thousand dollars. The cost of goods manufactured for the month was seven hundred sixty thousand dollars. And the ending finished goods inventory was one hundred fifty thousand dollars. What was the cost of goods sold for the month?
Managers often need to be able to predict how costs will change in response to changes in activity. The activity might be the output of goods or services or it might be some measure of activity internal to the company such as the number of purchase orders processed during a period. In this chapter, nearly all of the illustrations assume that the activity is the output of goods or services. In later chapters, other measures of activity will be introduced.
While there are other ways to classify costs according to how they react to changes in activity, in this chapter we introduce the simple variable and fixed classifications. Just about any cost will change if there is a big enough change in activity. There is some controversy concerning the proper definition of the “relevant range.” Some refer to the relevant range as the range of activity within which the company usually operates. We refer to the relevant range as the range of activity within which the assumptions about variable and fixed costs are valid. Either definition could be used—our choice was dictated by our desire to highlight the notion that fixed costs can change if the level of activity changes enough.
Total variable cost varies in direct proportion to changes in the level of activity. For example, your long distance telephone bill may be based on how many minutes your talk—the total bill varies with the number of minutes used.
Although variable costs change in total as the activity level rises and falls, variable cost per unit is constant. For example, the cost per long distance minute may be ten cents a minute.
Total fixed cost is constant within the relevant range. In other words, fixed costs do not change for changes in activity that fall within the “relevant range.” For example, your monthly basic telephone bill probably is a set amount and does not change based on the number of calls you make.
However, when expressed on a per unit basis, a fixed cost is inversely related to activity—the per unit cost decreases when activity rises and increases when activity falls. For example, the average fixed cost per local call decreases as more local calls are made.
It is helpful to think about variable and fixed cost behavior in a two by two matrix, as illustrated here. Take a few minutes and review this summary of cost behavior for variable and fixed costs.
Which of the following costs would be variable with respect to the number of cones sold at a Baskins and Robbins shop? (There may be more than one correct answer.)
A cost object is anything for which cost data are desired including products, customers, jobs, organizational subunits, etc. For purposes of assigning costs to cost objects costs are classified two ways:
Direct costs are costs that can be easily and conveniently traced to a unit of product or other cost object. Examples of direct costs are direct material and direct labor.
Indirect costs are costs that cannot be easily and conveniently traced to a unit of product or other cost object. An example of an indirect cost is manufacturing overhead. Common costs are indirect costs incurred to support a number of cost objects. These costs cannot be traced to any individual cost object.
It is important to realize that every decision involves a choice between at least two alternatives. The goal of making decisions is to identify those costs that are either relevant or irrelevant to the decision. Costs and benefits that differ between alternatives are relevant in a decision. All other costs and benefits are irrelevant and can and should be ignored.
Differential costs (or incremental costs) is a difference in cost between any two alternatives. A difference in revenue between two alternatives is called differential revenue. Differential costs can be either fixed or variable.
For example, assume you have a job paying one thousand five hundred dollars per month in your hometown. You have a job offer in a neighboring city that pays two thousand dollars per month. The commuting cost to the city is three hundred dollars per month. In this example, the differential revenue is five hundred dollars and the differential cost is three hundred dollars.
Opportunity cost is the potential benefit that is given up when one alternative is selected over another. These costs are not usually entered into the accounting records of an organization, but must be explicitly considered in all decisions.
A sunk cost is a cost that has already been incurred and that cannot be changed by any decision made now or in the future. Since sunk costs cannot be changed and therefore cannot be differential costs, they should be ignored in decision making. While students usually accept the idea that sunk costs should be ignored on an abstract level, like most people they often have difficulty putting this idea into practice.
In this chapter we learned that costs can be classified in a number of ways—depending on the purpose of the classification. It is important to note that the classifications of costs are not mutually exclusive. That is, a particular cost may be classified in many different ways—depending on the purpose of the classification. You may want to review the different cost classifications before continuing to the next chapter.
