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Gross profit margin = (gross profit ÷ revenue) × 100, where gross profit = revenue − cost of sales. Notes, worked examples and 10 questions answered.
Calculating and Applying Profitability Ratios & ARR (Part 1/3) is part of Analysing the financial performance of a business in GCSE AQA Business.
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Gross profit margin = (gross profit ÷ revenue) × 100, where gross profit = revenue − cost of sales. Notes, worked examples and 10 questions answered.
Use this lesson to stay inside Analysing the financial performance of a business while connecting the detail back to the wider Finance topic.
Read the core explanations from Calculating and Applying Profitability Ratios & ARR (Part 1/3) before testing yourself from memory.
A business has revenue of £200,000, cost of sales of £80,000, and operating expenses of £60,000. What is the net profit margin?
Profitability ratios convert profit figures into percentages, making it possible to compare businesses of different sizes, track performance over time, and benchmark against industry averages. For AQA GCSE, you need to calculate and interpret two key ratios: the gross profit margin and the net profit margin.
You also need to calculate the average rate of return (ARR), which helps a business decide whether an investment is worth making. All three rely on the same core skill: turning a financial figure into a meaningful percentage. That skill starts with understanding what each profit figure actually represents.
Before calculating any ratio, you need to be clear on what the two profit figures mean — because mixing them up is one of the most common errors in the exam.
Think of it this way: gross profit tells you how well the business manages what it sells; net profit tells you how well it manages everything else. A business with a high gross profit but low net profit has a cost control problem — its expenses are eating into its earnings.
Now that you have the two profit figures pinned down, you can turn them into ratios. Here is where the percentages come in.
Both ratios follow the same structure: take the relevant profit figure, divide it by revenue, and multiply by 100 to express it as a percentage. The formula is the same shape each time — only the profit figure changes.
Notice that both formulae divide by revenue, not by profit. This is the anchor point — revenue is the starting figure before any costs are removed, so it gives a fair basis for comparison.
Now let's walk through a full worked example so you can see exactly how to apply these formulae under exam conditions. The key habit to build is always writing the formula first, then substituting the numbers — this earns method marks even if you make an arithmetic slip. Confirmed calculations: Gross Profit Margin = 62.5%. Net Profit Margin = 37.5%. The difference between GPM and NPM is 25%, which reflects the portion of expenses relative to revenue — this observation holds when both ratios are calculated using the same revenue denominator.
Worked example: Calculating Gross Profit Margin and Net Profit Margin
Priya's Patisserie has the following financial data for the year: - Revenue: £120,000 - Cost of Sales: £45,000 - Operating Expenses: £30,000 Calculate (a) the gross profit margin and (b) the net profit margin. Show all working.
Answer: Gross Profit Margin = 62.5%. Net Profit Margin = 37.5%. Priya's patisserie retains 62.5p of every pound of revenue after direct costs, and 37.5p after all costs.
This is where students often slip up — let's check whether you have spotted the key relationship between the two ratios.
Calculating the ratio is only half the job. In the exam, you will almost always be asked to interpret the result — and that is where the marks for analysis and evaluation are won. A percentage on its own means very little without context.
There are three ways to give a ratio result meaning: compare it to a previous year (is the business improving?), compare it to a competitor or industry average (is the business performing well relative to others?), or compare it to a target set by the business itself.
Looking at this chart, Priya's Patisserie outperforms the industry average on both measures. Her gross profit margin of 62.5% compared to the industry average of 55% suggests she either prices her products at a premium or sources ingredients at lower cost than competitors. Her net profit margin of 37.5% versus the industry average of 28% indicates she also controls her operating expenses more effectively than most rivals.
This kind of comparison is exactly what examiners expect in a 4- or 6-mark question. State the ratio, compare it to a benchmark, and then explain what that difference means for the business — does it suggest a pricing advantage, a cost problem, or strong expense management?
Different stakeholders care about profitability ratios for different reasons. Shareholders use net profit margin to assess whether their investment is generating adequate returns. Managers use both ratios to identify whether cost of sales or operating expenses are the bigger problem. Lenders and suppliers may use these figures to judge the financial health of the business before extending credit.
Profitability ratios assess how well a business is currently performing. But businesses also need to decide whether to invest in new equipment, open new locations, or launch new products. The average rate of return is the tool used to evaluate whether a proposed investment is worthwhile.
The ARR answers a specific question: on average, what percentage return does this investment generate each year, relative to the amount invested? This allows a business to compare different investment options on a like-for-like basis, or to compare the ARR against the interest rate available from putting the money in a bank.
The calculation has two stages: first find the average annual profit, then express it as a percentage of the initial investment. Let's work through a realistic exam-style example step by step.
Worked example: Calculating the Average Rate of Return (ARR)
Mohammed is considering investing £80,000 in new bakery equipment. He estimates the equipment will generate the following net profits over four years: - Year 1: £12,000 - Year 2: £18,000 - Year 3: £22,000 - Year 4: £20,000 Calculate the ARR for this investment.
Answer: ARR = 22.5%. On average, the investment generates a 22.5% annual return on the £80,000 outlay, making it likely to be an attractive investment compared to lower-risk alternatives.
The ARR calculation relies on the same percentage skill as the profitability ratios — divide the relevant figure by the base figure and multiply by 100. The difference is that here the base figure is the initial investment, not revenue. Keeping that distinction clear is what separates a full-mark answer from a common error.
Ratio questions on the AQA paper follow a predictable pattern: calculate, then interpret. The calculation part is worth 2 marks (formula and correct answer); the interpretation part is where the remaining marks are awarded. Many students calculate correctly but then write a single vague sentence and lose the interpretation marks entirely.
The mark-winning structure for any ratio question is: state the formula → substitute the values → calculate the answer → compare to a benchmark → explain the business implication. Every step in that chain corresponds to marks on the mark scheme. Skipping the formula costs you a method mark even if your final answer is correct.
For ARR questions specifically, watch out for questions that give you cash inflows rather than profit figures. If the question provides cash inflows, you need to subtract the total initial investment from total cash inflows to get total net profit, and then divide by the number of years. Read the question carefully to check what figures you have been given.
Before finishing this section, test yourself on the full picture of what you have covered — this question brings together ratio calculation and interpretation in the way the exam will.
Published by Revise Right. Use the official specification reference to check the requirements for your course. Content updated: 2026-03-05.
Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.
Gross profit margin = (gross profit ÷ revenue) × 100, where gross profit = revenue − cost of sales. A patisserie with revenue of £120,000 and cost of sales of £45,000 has gross profit of £75,000 and a gross profit margin of 62.5%, keeping 62.5p of every £1 of revenue before operating expenses.
Net profit margin = (net profit ÷ revenue) × 100, where net profit = gross profit − operating expenses. With gross profit of £75,000, operating expenses of £30,000 and revenue of £120,000, net profit is £45,000 and the net profit margin is 37.5%. Always divide by revenue, not by gross profit.
To calculate ARR from yearly profits, add the profits, divide by the number of years, then divide by the initial investment and multiply by 100. Equipment costing £80,000 that earns £12,000, £18,000, £22,000 and £20,000 over four years makes £72,000 in total, an average of £18,000 a year and an ARR of 22.5%.
Profitability ratios are used by shareholders to judge whether their investment is generating adequate returns, by managers to identify whether cost of sales or operating expenses are the bigger problem, and by lenders and suppliers to judge financial health before extending credit.
Interpreting a profitability ratio means giving the result, a comparison and a business implication, comparing it with a previous year, a competitor or industry average, or a target. A gross profit margin of 62.5% against an industry average of 55% suggests premium pricing or lower ingredient costs than competitors.
Net profit margin must always be lower than gross profit margin because operating expenses are an additional deduction, so an NPM higher than the GPM means an error has been made. The gap equals expenses as a share of revenue: £30,000 of expenses on £120,000 of revenue explains the 25% gap between 62.5% and 37.5%.
An ARR of 22.5% means an investment generates, on average, a 22.5% annual return on the money invested. Mohammed's £80,000 bakery equipment earning £72,000 total net profit over four years averages £18,000 a year, far more attractive than a 4% bank interest rate.
ARR from cash inflows needs one extra step: the total initial investment is subtracted from total cash inflows to get total net profit, which is then divided by the number of years and expressed as a percentage of the initial investment. Using revenue or cash inflow figures in place of profit is a common error.
A 5% net profit margin can be good or bad depending on the business: it is normal in a supermarket context, but for a luxury brand it would indicate serious cost problems. A ratio only gains meaning when compared with a previous period, a competitor or an industry benchmark.
A rising gross profit margin, such as 62.5% compared with last year's 58%, suggests the business has improved its cost of sales management or increased its prices. Gross profit margin reflects how well a business manages what it sells.