The Concept and Calculation of Profit | 利润的概念与计算

📚 The Concept and Calculation of Profit | 利润的概念与计算

Profit is one of the most fundamental concepts in economics. It is the financial reward that entrepreneurs earn for taking risks and organising factors of production. In this revision guide, we will explore the meaning of profit, distinguish between its different types, and learn how to calculate it in a range of A-Level scenarios.

利润是经济学中最基本的概念之一。它是企业家承担风险和组织生产要素所获得的财务回报。在本复习指南中，我们将探讨利润的含义，区分不同类型的利润，并学习如何在各种A-Level情景中计算利润。

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1. Total Revenue, Total Cost and Profit | 总收益、总成本与利润

Before understanding profit, we must first define revenue and cost. Total Revenue (TR) is the total income a firm receives from selling its output, calculated as price (P) multiplied by quantity sold (Q):

在理解利润之前，我们必须先定义收益与成本。总收益（TR）是厂商通过销售其产出所获得的总收入，计算公式为价格（P）乘以销售量（Q）：

TR = P × Q

Total Cost (TC) is the total expense incurred by a firm in producing its output. It includes both fixed costs (FC), which do not vary with output, and variable costs (VC), which do vary with output:

总成本（TC）是厂商在生产其产出过程中发生的全部费用。它包括不随产量变化的固定成本（FC）和随产量变化的可变成本（VC）：

TC = FC + VC

Profit (π) is then defined as the difference between total revenue and total cost:

利润（π）因此被定义为总收益与总成本之间的差额：

Profit (π) = TR − TC

If TR exceeds TC, the firm makes a profit. If TR is less than TC, the firm makes a loss. In numerical terms, profit can be positive, zero or negative.

如果TR大于TC，厂商盈利；如果TR小于TC，厂商亏损。从数值上看，利润可以为正、为零或为负。

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2. Accounting Profit vs Economic Profit | 会计利润与经济利润

Accountants and economists measure profit differently. Accounting profit only subtracts explicit costs from total revenue. Explicit costs are the actual monetary payments made to suppliers, workers and landlords, such as wages, rent and raw materials.

会计师和经济学家衡量利润的方式不同。会计利润只从总收益中减去显性成本。显性成本是向供应商、工人和地主实际支付的货币款项，例如工资、租金和原材料费用。

Accounting Profit = TR − Explicit Costs

Economic profit, by contrast, subtracts both explicit costs and implicit costs from total revenue. Implicit costs include the opportunity cost of the owner’s time, capital and any other resources supplied by the owner. This distinction is essential for A-Level candidates.

相比之下，经济利润从总收益中同时减去显性成本和隐性成本。隐性成本包括所有者时间、资本以及所有者提供的任何其他资源的机会成本。这一区别对A-Level考生至关重要。

Economic Profit = TR − Explicit Costs − Implicit Costs

For example, if a business earns $100,000 in revenue and pays $70,000 in explicit costs, its accounting profit is $30,000. However, if the owner could have earned $25,000 working for another firm, the economic profit is only $5,000.

例如，如果一家企业收入为100,000美元，显性成本为70,000美元，其会计利润为30,000美元。然而，如果所有者本可以在另一家企业工作赚取25,000美元，那么经济利润仅为5,000美元。

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3. Normal Profit and Supernormal Profit | 正常利润与超正常利润

Normal profit is the minimum level of profit required to keep a firm operating in its current industry in the long run. It is the opportunity cost of the entrepreneur’s resources and is therefore included as a cost in economic analysis. When a firm earns normal profit, economic profit is zero, but accounting profit is positive.

正常利润是长期内使厂商继续在当前行业中经营所需的最低利润水平。它是企业家资源的机会成本，因此在经济分析中被计入成本。当厂商获得正常利润时，经济利润为零，但会计利润为正。

Supernormal profit, also called abnormal profit or economic profit in some textbooks, occurs when total revenue exceeds total costs including normal profit. This means economic profit is greater than zero.

超正常利润，在某些教材中也称为超额利润或经济利润，发生在总收益超过总成本（包括正常利润）之时。这意味着经济利润大于零。

Supernormal profit signals that resources are being used efficiently and attracts new entrants into the industry. In perfect competition, new firms enter, supply rises, price falls, and supernormal profit is eliminated in the long run. Only normal profit remains.

超正常利润表明资源得到了有效利用，并吸引新厂商进入该行业。在完全竞争中，新厂商进入、供给增加、价格下降，超正常利润在长期中被消除，只剩下正常利润。

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4. Calculating Profit: Worked Examples | 计算利润：例题演示

Let us apply the formulas to typical examination questions.

让我们将公式应用于典型的考试题目。

Example 1: A firm sells 500 units at a price of $20 per unit. Its fixed costs are $3,000 and its average variable cost is $10 per unit. Calculate total revenue, total cost and profit.

例题1：某厂商以每单位20美元的价格销售500单位产品。其固定成本为3,000美元，平均可变成本为每单位10美元。计算总收益、总成本和利润。

TR = P × Q = 20 × 500 = $10,000

Total revenue is therefore $10,000.

因此总收益为10,000美元。

VC = AVC × Q = 10 × 500 = $5,000

TC = FC + VC = 3,000 + 5,000 = $8,000

Total cost is therefore $8,000.

因此总成本为8,000美元。

Profit = TR − TC = 10,000 − 8,000 = $2,000

The firm makes an accounting profit of $2,000.

该厂商获得2,000美元的会计利润。

Example 2: Using the information above, if the owner could have earned $2,500 in their next best alternative job, calculate the economic profit.

例题2：利用上述信息，如果所有者本可以在次优选择的工作中赚取2,500美元，计算经济利润。

Economic Profit = 2,000 − 2,500 = −$500

The firm is making a loss of $500 in economic terms, even though its accounting profit is positive. This shows the importance of considering opportunity costs.

尽管该厂商的会计利润为正，但从经济角度看它亏损了500美元。这表明考虑机会成本的重要性。

Example 3: A firm has fixed costs of $4,000, a price of $12 per unit and an average variable cost of $7 per unit. Calculate the break-even output.

例题3：某厂商固定成本为4,000美元，价格为每单位12美元，平均可变成本为每单位7美元。计算盈亏平衡产量。

Break-even output = FC ÷ (P − AVC) = 4,000 ÷ (12 − 7) = 800 units

At 800 units, total revenue equals total cost and the firm earns zero profit. Selling more than 800 units generates supernormal profit; selling fewer generates a loss.

在800单位时，总收益等于总成本，厂商获得零利润。销售超过800单位产生超正常利润；销售低于800单位则产生亏损。

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5. Average Revenue and Marginal Revenue | 平均收益与边际收益

Average revenue (AR) is the revenue earned per unit sold, calculated as total revenue divided by quantity. Since price equals TR ÷ Q for any given level of output, AR is equal to price.

平均收益（AR）是每销售一单位所获得的收益，计算公式为总收益除以数量。由于在任意给定产出水平下价格等于TR ÷ Q，因此AR等于价格。

AR = TR ÷ Q = P

Marginal revenue (MR) is the additional revenue gained from selling one more unit of output:

边际收益（MR）是多销售一单位产出所获得的额外收益：

MR = ΔTR ÷ ΔQ

These concepts are essential when analysing profit maximisation. A firm maximises profit when marginal revenue equals marginal cost.

这些概念在分析利润最大化时至关重要。当边际收益等于边际成本时，厂商实现利润最大化。

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6. The Profit-Maximising Condition | 利润最大化的条件

The profit-maximising level of output occurs where the marginal cost of producing one extra unit equals the marginal revenue from selling it:

利润最大化的产出水平发生在多生产一单位的边际成本等于销售该单位的边际收益之时：

MR = MC

If MR is greater than MC, the extra unit adds more to revenue than to cost, so producing it increases total profit. If MR is less than MC, the extra unit adds more to cost than to revenue, so producing it reduces total profit.

如果MR大于MC，额外一单位增加的收益大于增加的成本，因此生产该单位会增加总利润。如果MR小于MC，额外一单位增加的成本大于增加的收益，因此生产该单位会减少总利润。

At the profit-maximising output, the firm should also check whether it is making a profit or a loss overall by comparing price with average total cost. If price is above average total cost, the firm earns supernormal profit; if price is below average total cost but above average variable cost, the firm minimises its losses in the short run.

在利润最大化的产出水平上，厂商还应通过比较价格与平均总成本来判断整体是盈利还是亏损。如果价格高于平均总成本，厂商获得超正常利润；如果价格低于平均总成本但高于平均可变成本，厂商在短期内将亏损最小化。

Profit maximisation is different from revenue maximisation (MR = 0) and sales maximisation. A firm aiming to maximise profit will set output where MR = MC

Published by TutorHao | A-Level Economics Revision Series | aleveler.com

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