AQA A-Level Economics (7136)

## Learning Outcomes

- Define profit and calculate it using total revenue and total cost
- Distinguish clearly between accounting profit and economic profit
- Explain the difference between normal profit and supernormal profit
- Apply the profit-maximising rule of **MC = MR**
- Interpret when a firm should keep producing, minimise losses, or shut down in the short run
- Use diagram logic correctly to identify profit, loss, and the size of supernormal profit
- Evaluate why profit matters in a market economy and why it may persist in some markets

## AQA A-Level Economics (7136) Syllabus

For the AQA A-Level Economics (7136), you are expected to understand profit within production, costs and revenue, with a focus on the following syllabus points:

- Know that **profit = total revenue − total cost**
- Identify the difference between **total revenue**, **average revenue**, and **profit**
- Explain the difference between **accounting profit** and **economic profit**
- Understand that **normal profit** is the minimum profit needed to keep resources in their current use in the long run
- Know that **supernormal profit** and **abnormal profit** mean the same thing
- Explain why firms are usually assumed to aim for **profit maximisation**
- Apply the rule that profit is maximised where **marginal cost equals marginal revenue**
- Understand the short-run shut-down decision using **average revenue**, **average cost**, and **average variable cost**

## Test Your Knowledge

_Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, look more closely at that area during your revision._

1. What is the difference between revenue and profit?
2. Why does normal profit not mean the same as zero profit in everyday language?
3. How do you identify the profit-maximising level of output?
4. When can a firm continue producing even if it is making a loss?
5. What is the difference between accounting profit and economic profit?

## Introduction

Profit is one of the most tested ideas in microeconomics because it links costs, revenue, market structure, and firm behaviour. In simple terms, profit shows whether a firm is earning more from sales than it is sacrificing in costs. However, AQA expects more than the everyday meaning of profit. You need to understand how economists treat opportunity cost, why normal profit is counted as a cost, and how firms decide whether to keep producing.

This topic also matters because profit helps explain entry and exit, competition, innovation, and efficiency. In exam answers, strong students move beyond the formula and explain what profit signals in a market.

> **Key Term: profit**
> The difference between total revenue and total cost of production.

### Calculating profit and avoiding basic confusion

The starting point is the core formula:

- **Profit = Total Revenue (TR) − Total Cost (TC)**

Total revenue is the money a firm receives from selling output:

- **TR = Price × Quantity sold**

If total revenue is greater than total cost, the firm makes a profit. If total revenue is less than total cost, the firm makes a loss.

A common mistake is to confuse profit with revenue. Revenue is the money coming in from sales only. Profit is what is left after costs have been taken into account.

> **Key Term: total revenue (TR)**
> All the money received by a firm from selling its total output.
>
> **Key Term: total cost (TC)**
> The total cost of production, including fixed and variable costs, and in economics also including opportunity costs when economic profit is considered.

You also need **average revenue**:

- **AR = TR ÷ Quantity**
- In a single-product firm, **AR = price**

This matters because many profit diagrams use **AR** rather than directly writing price.

> **Key Term: average revenue (AR)**
> Total revenue divided by output; in most textbook cases, it is equal to the price of the product.

### Worked example: calculating profit

A firm sells 500 units at £12 each.

Step 1: Calculate total revenue

- TR = Price × Quantity
- TR = £12 × 500
- TR = **£6000**

Step 2: Calculate total cost

Suppose:

- Fixed costs = **£1200**
- Variable costs = **£3800**

So:

- TC = Fixed costs + Variable costs
- TC = £1200 + £3800
- TC = **£5000**

Step 3: Calculate profit

- Profit = TR − TC
- Profit = £6000 − £5000
- Profit = **£1000**

So the firm makes a profit of **£1000**.

> **Test Tip:** In calculation questions, write out each step with labels: TR, TC, then Profit. This reduces simple errors and gains method marks.

Common student errors:

- Using revenue as if it were profit
- Forgetting to subtract total cost
- Mixing up average values and total values
- Forgetting that output must be multiplied by the per-unit figure when finding totals

### Accounting profit, economic profit, and why opportunity cost matters

Economists use a wider idea of cost than accountants often do. This is why a business may appear profitable in everyday terms but only be earning normal profit economically.

**Accounting profit** only subtracts explicit costs. These are direct money payments such as wages, rent, and raw materials.

**Economic profit** subtracts both explicit costs and implicit costs. Implicit costs are opportunity costs, such as the return the owner could have earned elsewhere.

> **Key Term: accounting profit**
> Total revenue minus explicit costs only.
>
> **Key Term: economic profit**
> Total revenue minus both explicit costs and implicit costs.
>
> **Key Term: implicit costs**
> The opportunity costs of resources used by the firm for which no direct money payment is made.

Suppose a business has:

- Total revenue = **£200,000**
- Explicit costs = **£150,000**
- Implicit costs = **£50,000**

Accounting profit:

- £200,000 − £150,000 = **£50,000**

Economic profit:

- £200,000 − (£150,000 + £50,000) = **£0**

So the firm has a positive accounting profit, but zero economic profit.

That zero economic profit is called **normal profit**.

> **Key Term: normal profit**
> The minimum profit needed to keep the entrepreneur and the firm's resources in their current use in the long run; it is zero economic profit.

This is one of the most important distinctions in the topic. Normal profit does not mean the owner gets nothing. It means the firm is earning just enough to cover all explicit costs and the opportunity cost of enterprise.

If economic profit is above zero, the firm is earning **supernormal profit**.

> **Key Term: supernormal profit**
> Profit above normal profit; it exists when total revenue exceeds total cost including opportunity cost.
>
> **Key Term: abnormal profit**
> Another term for supernormal profit.

Normal profit is treated as a cost because the entrepreneur could use their time, money, and skills elsewhere. If the firm does not at least match that alternative return, resources will leave in the long run.

> **Test Tip:** If an exam question says costs include opportunity cost, then TR = TC means normal profit, not “no profit” in the everyday sense.

Common student errors:

- Saying normal profit means the firm is not earning anything
- Forgetting that normal profit is an implicit cost
- Treating abnormal profit and supernormal profit as different concepts

### Profit maximisation and the rule MC = MR

Economists usually assume firms aim to maximise profit. That means choosing the output where the difference between total revenue and total cost is greatest.

> **Key Term: profit maximisation**
> Producing at the level of output where total profit is greatest.

The rule is:

- A firm maximises profit where **marginal cost = marginal revenue**
- More precisely, profit is maximised where **MC = MR** and **MC is rising**

Why? Because:

- If **MR > MC**, producing one more unit adds more to revenue than to cost, so profit rises
- If **MC > MR**, producing one more unit adds more to cost than to revenue, so profit falls

So the firm should keep expanding output until the two are equal.

> **Key Term: marginal revenue (MR)**
> The change in total revenue from selling one more unit of output.
>
> **Key Term: marginal cost (MC)**
> The change in total cost from producing one more unit of output.

### Worked example: finding the profit-maximising output

Consider this data:

| Output | TR (£) | TC (£) |
| ------ | -----: | -----: |
| 0      |      0 |     10 |
| 1      |     20 |     14 |
| 2      |     38 |     19 |
| 3      |     54 |     28 |
| 4      |     68 |     44 |
| 5      |     80 |     80 |
| 6      |     90 |     93 |

Step 1: Calculate profit at each output

- Output 0: 0 − 10 = **−10**
- Output 1: 20 − 14 = **6**
- Output 2: 38 − 19 = **19**
- Output 3: 54 − 28 = **26**
- Output 4: 68 − 44 = **24**
- Output 5: 80 − 80 = **0**
- Output 6: 90 − 93 = **−3**

Step 2: Identify the highest profit

The highest profit is **£26** at output **3**.

So the profit-maximising output is **3 units**.

Step 3: Identify normal profit

At output **5**, TR = TC, so economic profit is **0**. This is **normal profit**, assuming costs include opportunity cost.

Step 4: Find marginal revenue between 4 and 5 units

- MR = Change in TR
- MR = £80 − £68
- MR = **£12**

This type of question is common because it checks calculation and understanding at the same time.

Common student errors:

- Choosing the output where TR is highest instead of where profit is highest
- Forgetting that losses are negative profit
- Saying TR = TC means supernormal profit

### Diagram logic: profit, loss, and shut-down decisions

In diagram questions, follow a strict order.

First, find output where **MC = MR**.

Second, move up to the **AR** curve to find revenue per unit.

Third, compare **AR** with **AC** at that output.

This gives three outcomes:

- **AR > AC**: supernormal profit
- **AR = AC**: normal profit
- **AR < AC**: loss

If the firm earns supernormal profit, total supernormal profit is:

- **(AR − AC) × output**

This is a rectangle on the diagram.

A very common exam mistake is to jump straight to AR and AC without finding the profit-maximising output first. The firm does not maximise profit where AR = AC. That only identifies normal profit once the correct output has already been found.

> **Test Tip:** In diagram questions, always write: “Output is determined where MC = MR.” Then classify profit by comparing AR and AC at that output.

### Short-run losses and the shut-down point

A firm may keep producing in the short run even when it makes a loss. This is because fixed costs still have to be paid even if production stops.

The key comparison in the short run is between **AR** and **AVC**.

- If **AR > AVC**, the firm should continue producing in the short run because it covers variable costs and contributes something towards fixed costs
- If **AR = AVC**, the firm is at the **shut-down point**
- If **AR < AVC**, the firm should shut down immediately in the short run
  > **Key Term: shut-down point**
  > The point where average revenue equals average variable cost; below this, the firm should cease production in the short run.

This means a firm can be making a loss and still keep operating for a time.

Side-by-side distinction:

- **AR > AC**: supernormal profit
- **AR = AC**: normal profit
- **AVC < AR < AC**: loss, but continue in the short run
- **AR < AVC**: shut down in the short run

This distinction is very important in multiple-choice questions.

### Why profit matters and how to evaluate it

Profit has several roles in a market economy.

First, it acts as a **signal**. High profits suggest resources are being used in a way consumers value. This can attract new firms into the industry.

Second, profit provides an **incentive**. Entrepreneurs may take risks and innovate if they expect future supernormal profits.

Third, profit can support **investment**. Retained profit can fund new machinery, research, staff training, or expansion.

However, profit is not always a sign of good outcomes. Very high profits may result from strong barriers to entry or monopoly power, not just efficiency. In competitive or contestable markets, supernormal profit is more likely to be temporary because new firms enter and increase competition. In markets with high barriers to entry, supernormal profit may persist for longer.

### How to structure an evaluative answer

For a 15- or 25-mark response on profit, use a clear chain of reasoning.

Start by defining the key terms, such as normal profit, supernormal profit, and profit maximisation.

Then apply theory to the context:

- refer to revenue, costs, market power, or barriers to entry
- explain whether profits are likely to be short-run or long-run
- show how entry, exit, or innovation changes the result

On the one hand:

- profit encourages efficiency, innovation, and investment

On the other hand:

- high profit may reflect weak competition, consumer exploitation, or barriers to entry

It depends on:

- the market structure
- the level of contestability
- whether profit comes from efficiency or market power
- whether you are looking at the short run or long run

Strong evaluation uses these conditions rather than making a generic final paragraph.

## Key Point Checklist

_This article has covered the following key knowledge points:_

- Profit is **total revenue minus total cost**
- Total revenue equals **price × quantity sold**
- Average revenue is **TR ÷ output** and usually equals price in a single-product firm
- Accounting profit subtracts only explicit costs
- Economic profit subtracts both explicit and implicit costs
- Normal profit is the minimum return needed to keep resources in their current use in the long run
- Normal profit means **zero economic profit**, not zero accounting profit
- Supernormal profit and abnormal profit mean the same thing
- Profit is maximised where **MC = MR** and marginal cost is rising
- On a diagram, output is found first using **MC = MR**, then profit or loss is identified by comparing **AR** and **AC**
- A firm can continue producing in the short run while making a loss if **AR is above AVC**
- The shut-down point is where **AR = AVC**

## Key Terms and Concepts

- profit
- total revenue (TR)
- total cost (TC)
- average revenue (AR)
- accounting profit
- economic profit
- implicit costs
- normal profit
- supernormal profit
- abnormal profit
- profit maximisation
- marginal revenue (MR)
- marginal cost (MC)
- shut-down point


Production, Costs and Revenue - Profit