Business costs, revenues and profit
Economics· 4EC1 1.2.3· 35 min read
1. Calculating Costs, Revenue and Profit★★☆☆☆⏱ 10 min
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Core Business Financial Calculations
The six core formulae for this topic are: 1. Total Revenue (TR) = Price (P) × Quantity (Q) sold; 2. Total Fixed Costs (TFC) = Costs that do not change with output; 3. Total Variable Costs (TVC) = Costs that rise as output increases; 4. Total Costs (TC) = TFC + TVC; 5. Average Cost (AC) = TC ÷ Q; 6. Profit = TR - TC. A loss occurs when TR < TC.
A local bakery sells 200 loaves of bread per week at a price of £3 each. Its weekly fixed costs are £150, and variable cost per loaf is £1.20. Calculate the bakery’s weekly profit, showing all workings.
- 1
Calculate total revenue first:
- 2
Calculate total variable costs:
- 3
Calculate total costs:
- 4
Calculate profit:
Exam tip:
Always show every step of your calculations for 4EC1 exam questions: even if your final answer is wrong, you can still earn method marks for correct workings.
2. Economies of Scale★★★☆☆⏱ 10 min
Economies of Scale
The fall in long-run average cost per unit as a business increases its output. These cost savings can come from internal factors specific to the business, or external factors affecting all businesses in an industry or location.
Internal economies of scale types: purchasing (bulk buying discounts), marketing (lower per-unit advertising costs), technical (specialised machinery/division of labour), financial (lower loan interest rates), managerial (specialist staff), risk-bearing (product diversification to spread risk)
External economies of scale types: skilled labour pool (local workers with industry-specific training), infrastructure (industry-specific local transport/utilities), access to nearby suppliers, clustered similar businesses (knowledge sharing)
Explain how a large supermarket chain benefits from purchasing economies of scale, compared to a small independent corner shop.
- 1
Define purchasing economies of scale: cost savings from bulk buying discounts when firms purchase large volumes of inputs.
- 2
Apply to context: The supermarket chain buys 10,000 tins of baked beans directly from a manufacturer, negotiating a 25% discount per tin. The small shop only buys 100 tins, so it pays full price per tin.
- 3
Link to average cost: The supermarket has a lower per-unit cost for baked beans, so it can sell at a lower price while earning a higher profit margin than the small shop.
Exam tip:
When asked to explain an economy of scale, always link your answer directly to lower average cost: many students lose marks for only describing the type, not explaining how it reduces cost per unit.
3. Diseconomies of Scale★★★☆☆⏱ 8 min
Diseconomies of Scale
The rise in long-run average cost per unit as a business grows beyond a certain size, caused by inefficiencies in very large organisations.
Common types: bureaucracy (too many management layers slowing decisions), communication problems (messages misinterpreted across large teams), lack of control (senior managers cannot monitor all operations), distance between management and workers (low staff morale reducing productivity)
A delivery company grows from 50 drivers to 5,000 drivers operating across 10 countries, and sees its average cost per delivery rise. Explain one diseconomy of scale that could cause this.
- 1
Identify a relevant diseconomy of scale: communication problems.
- 2
Explain the cause: Senior management at head office cannot communicate policy changes directly to all 5,000 drivers, so local managers often misinterpret new rules, leading to inefficient routing and delayed deliveries.
- 3
Link to average cost: Delayed deliveries mean the company spends more on fuel and overtime pay per delivery, raising its average cost per unit.
4. Long-Run Average Cost (LRAC) Curve★★★★☆⏱ 7 min
Long-Run Average Cost (LRAC) Curve
A U-shaped curve that shows how average cost per unit changes as a business increases its output in the long run, when all factors of production can be adjusted.
The LRAC curve has three core features you must label for exam questions: 1. Downward-sloping left section = internal economies of scale; 2. Lowest point = minimum efficient scale (most efficient output level); 3. Upward-sloping right section = diseconomies of scale. Axes must be labelled: vertical = long-run average cost (£ per unit), horizontal = output (quantity produced).
Draw a fully annotated LRAC curve for a manufacturing business, including all features required for Edexcel IGCSE Economics exams.
- 1
Draw and label the axes correctly: Vertical axis = Long-run average cost (£ per unit), Horizontal axis = Output (units per year).
- 2
Draw a smooth U-shaped curve across the axes.
- 3
Annotate the three required features: 1. Downward sloping left section: Internal economies of scale; 2. Lowest point of the curve: Minimum efficient scale; 3. Upward sloping right section: Diseconomies of scale.
Exam tip:
You do not need to draw any other cost curves (like marginal cost or short-run average cost) alongside the LRAC curve for 4EC1: adding extra out-of-scope curves wastes time and can lead to lost marks if labelled incorrectly.
5. Common Pitfalls
Wrong move:
Forgetting to show workings when calculating profit or costs
Why:
Exam questions award method marks for correct steps even if the final answer is wrong, so skipping steps loses easy marks.
Correct move:
Write every calculation step separately, clearly labeling what you are calculating at each stage
Wrong move:
Confusing total cost with average cost when explaining economies of scale
Why:
Economies of scale refer to falling per-unit cost, not falling total cost (total cost always rises as output increases)
Correct move:
Explicitly reference "average cost per unit" every time you describe economies or diseconomies of scale
Wrong move:
Mixing up internal and external economies of scale
Why:
Examiners often ask to identify which type a given example refers to, so misclassification loses all marks for that part
Correct move:
Ask: "Does this benefit only one growing firm, or all firms in the area/industry?" If only one, it is internal; if all, it is external
Wrong move:
Drawing the LRAC curve with incorrect axes labels
Why:
Axis labels are worth 1 mark in diagram questions, so swapping cost and output axes gives you zero for that part
Correct move:
Always label the vertical axis "Long-run average cost (£ per unit)" and horizontal axis "Output" before drawing the curve
Wrong move:
Calculating average cost as fixed cost divided by quantity
Why:
Average cost includes both fixed and variable costs, so omitting variable costs gives an incorrect final answer
Correct move:
Always calculate total cost first (TFC + TVC) before dividing by quantity to get average cost
6. Quick Reference Cheatsheet
Concept | Formula/Definition | Key Exam Note |
|---|---|---|
Total Revenue | TR = P × Q | Use quantity sold, not quantity produced |
Total Costs | TC = TFC + TVC | Fixed costs do not change with output, variable costs do |
Average Cost | AC = TC ÷ Q | Always refers to per-unit total cost |
Profit | TR - TC | Negative value = loss |
Internal Economies of Scale | Cost savings for one growing firm | Types: purchasing, marketing, technical, financial, managerial, risk-bearing |
External Economies of Scale | Cost savings for all firms in an area/industry | Types: skilled labour, infrastructure, supplier access, clustered businesses |
Diseconomies of Scale | Rising AC for very large firms | Types: bureaucracy, communication issues, lack of control, management-worker distance |
LRAC Curve | U-shaped curve of AC vs output | Annotate EoS, minimum efficient scale, diseconomies of scale |
7. Frequently Asked
Do I need to draw marginal cost curves for this topic?
No, for Edexcel IGCSE Economics (4EC1), you only need to draw and annotate the single U-shaped long-run average cost (LRAC) curve. Marginal cost, average fixed cost and average variable cost curves are out of scope for this sub-topic.
What is the difference between internal and external economies of scale?
Internal economies of scale are cost benefits that arise from within a single business as it grows larger. External economies of scale are cost benefits that affect all businesses in a given industry or location, regardless of individual firm size.
Going deeper
What's Next
Now that you have mastered business costs, revenues and profit, you can move on to studying the next sub-topic in Edexcel IGCSE Business Economics: business growth and competitive markets. This knowledge will also be critical for answering data response questions on business performance in Paper 1, and for evaluating the impact of business size on market prices and consumer choice in extended response questions. Make sure to practice calculation questions and LRAC diagram drawing regularly to retain these skills for your exam.