Market Size
"The total level of sales of all producers within a market."
Can be measured in 2 ways:
- Volume of sales (number of units sold)
- Value of goods sold (sales revenue)
L4: Market Data
Revision and practice on calculating, interpreting and analysing market data.
Key vocabulary: Market Size, Market Share, Market Growth
Key Concepts
Market Share
"The percentage of one firm's share of the total sales in the market."
Calculated by:
Market Share (%) = (Total sales of firm's product ÷ Total market sales in time period) × 100
Market Growth
The percentage increase in the total size of a market over a given period. A growing market creates opportunities for new and existing businesses.
Calculated by:
Market Growth (%) = ((New Market Size − Old Market Size) ÷ Old Market Size) × 100
Using Market Data
Businesses need data to understand the markets they operate in and make informed marketing decisions. Key marketing data includes market size, market share, market growth and trends.
How businesses use marketing data:
- Market size: tells a business how big the opportunity is. A large and growing market is more attractive than a small or shrinking one.
- Market share: shows how a business is performing relative to competitors.
- Market growth: helps businesses decide where to invest. Fast-growing markets offer more opportunities but may also attract more competitors. Businesses often use index numbers to track changes in market size over time.
- Trend analysis: identifying changes in consumer behaviour, technology or demographics that might create opportunities or threats.
Real-World Case Studies
PureGym — market leadership in a fast-growing sector
The UK gym and fitness market is now worth around £3.1 billion, and PureGym is its largest gym operator by number of clubs and members, with revenue of roughly £396 million in 2025 — second only to David Lloyd Leisure by revenue among UK operators. PureGym has continued expanding through 2026, opening 15 new UK gyms in the first half of the year alone. This shows how a business can hold a strong market share (by member numbers) without necessarily having the highest revenue — David Lloyd's premium, higher-priced clubs generate more revenue from fewer, higher-spending members, while PureGym's low-cost model wins on volume.
Source: verified via search, September 2026 — WellNation coverage of PureGym's 2026 results, and PureGym investor financial reports.
Vinted — a market growing fast enough to reshape an industry
The UK second-hand fashion market is now worth more than £7 billion and has been growing at around 20% a year since 2019 — nearly one in four UK fashion purchases now involves resale. Vinted has grown alongside this trend to more than 17 million UK users, making it the UK's third-largest fashion retailer by customer numbers, behind only Primark and Next. This is a clear example of market growth creating opportunity: a market growing this quickly attracts new entrants and lets an existing player like Vinted grow its own market share rapidly, rather than having to fight competitors for a share of a static market.
Source: verified via search, September 2026 — Barclays and BusinessGreen coverage of the UK resale market and Vinted's UK user growth.
Quick Quiz
Pick an answer for instant feedback. Your score is just for you — it isn't saved anywhere.
1. A firm has sales of £150,000 in a market worth £1,000,000 in total. What is its market share?
2. A market grows from £800,000 to £1,000,000 in a year. What is the market growth?
3. A brand's sales of £40,000 represent an 8% market share. What is the size of the whole market?
4. Which of these is measured in volume rather than value?
5. Why might a fast-growing market attract more competitors?
Score: 0 / 0
Fill in the Blank
Tap the word or phrase that correctly completes each formula.
1. Market Share (%) = (Total sales of firm's product ÷ ____) × 100.
2. Market Growth (%) = ((New Market Size − Old Market Size) ÷ ____) × 100.
3. Market size can be measured either by volume of sales, or by ____.
4. To find the whole market from one firm's market share, first calculate ____ of the market.
Score: 0 / 0
Quick Knowledge Check
Short, snappy recall questions — tap to reveal the answer.
How is market share calculated? (1 mark)
(Total sales of firm's product ÷ Total market sales) × 100.
State two ways market size can be measured. (2 marks)
Volume of sales (units sold) and value of sales (sales revenue).
What is market growth? (1 mark)
The percentage increase in the total size of a market over a given period.
Key Term Flashcards
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Market Size
The total level of sales of all producers within a market — measured by volume (units sold) or value (sales revenue).
Market Share
The percentage of one firm's share of the total sales in the market. Market Share (%) = (Firm's sales ÷ Total market sales) × 100.
Market Growth
The percentage increase in the total size of a market over a given period. Market Growth (%) = ((New size − Old size) ÷ Old size) × 100.
Index numbers
A way businesses track changes in market size over time, using a base value (usually 100) to compare growth or decline across different years.
Trend analysis
Identifying changes in consumer behaviour, technology or demographics that might create opportunities or threats for a business.
Market map
A diagram plotting competing products or brands against two variables (e.g. price and quality) to help a business spot gaps in a market.
A*/A Stretch
Synoptic link
Connecting to market capitalisation (Unit 3.1.2): Market share and market capitalisation both measure a firm's relative size, but in different ways — market share compares a firm's sales to total market sales, while market cap compares a firm's share price × shares issued to other firms' equivalent values. A firm can have a high market share but a relatively low market cap (or vice versa) if investors have different expectations about its future growth — this is a good way to show synoptic thinking between marketing and finance topics in an exam answer.
Examiner's eye
In market share and market growth calculation questions, always show your working and state the correct unit (%). Markers give method marks even if your final answer is wrong due to a small arithmetic slip — but only if the formula and substitution are clearly shown, not just a final number.
Try This With AI
Before using this: AI tools can get facts or mark scheme details wrong, and quality varies by tool. Always check anything factual against your notes or ask your teacher.
Give me three short market share and market growth calculation problems, similar in style to an AQA A-Level Business exam, with the numbers hidden until I ask for the answer. After I attempt each one, mark my working and tell me whether I've shown the correct formula, not just the correct final number.