SingaporeAccountingSyllabus dot point

How well does a business turn its sales into profit?

Calculate and interpret the gross profit margin and the profit margin

A simple answer to the N(A)-Level Principles of Accounts outcome on profitability ratios. The gross profit margin and the profit margin, how to calculate each, and what a change in them tells the owner.

Generated by Claude Opus 4.89 min answerUpdated 2026-06-06

Reviewed by: AI editorial process; not yet individually human-reviewed

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What this dot point is asking
The answer
Examples in context
Try this

What this dot point is asking

SEAB wants you to calculate and interpret the gross profit margin and the profit margin. Profitability is the headline measure of how a business is doing, and the exam rewards explaining a ratio more than just computing it. The central insight is that profitability has layers: the margin after the cost of goods (gross profit margin) and the margin after all expenses (profit margin), and comparing them shows where profit is made or lost.

The answer

The two ratios

Ratio	Formula	Measures
Gross profit margin	$\dfrac{\text{gross profit}}{\text{sales}} \times 100$	Trading margin per dollar of sales
Profit margin	$\dfrac{\text{profit for the year}}{\text{sales}} \times 100$	Profit per dollar of sales after all expenses

Both are percentages of sales, so they are easy to compare across years or businesses of different size.

What each one means

Gross profit margin shows how much of each sales dollar is left after paying for the goods sold. A higher margin means the business buys cheaply and sells well.
Profit margin shows how much of each sales dollar is left after all expenses (wages, rent, electricity). It is always lower than the gross margin, because it takes more costs off.

Reading them together

The gap between the two margins is the running expenses. Comparing them is powerful:

A falling gross profit margin points to a trading problem: lower selling prices or higher cost of goods.
A steady gross profit margin but falling profit margin points to higher running expenses, not trading.

Worked example

A sole trader reports sales $\$ 80,000 $, gross profit$ \ $32\,000$ and profit for the year $\$ 12,000 $. Last year the gross profit margin was$ 40% $and the profit margin$ 20%$. Calculate this year's margins and comment.

Step 1: Gross profit margin

\frac{32\,000}{80\,000} \times 100 = 40\%

Step 2: Profit margin

\frac{12\,000}{80\,000} \times 100 = 15\%

Step 3: Compare with last year

Ratio	Last year	This year
Gross profit margin	40%	40%
Profit margin	20%	15%

Step 4: Comment

The gross profit margin is unchanged at $40\%$ , so trading (pricing and cost of goods) is the same. But the profit margin has fallen from $20\%$ to $15\%$ , which means running expenses have risen and taken a bigger share of the gross profit. The owner should review expenses such as wages or rent.

Examples in context

Example 1. A supplier price rise. A shop's supplier raises prices, but the shop keeps its selling prices the same. The gross profit margin falls because each sale now costs more, even though sales volume is unchanged. The drop at the gross-margin level points straight to a trading cause, telling the owner to renegotiate with suppliers or raise prices.

Example 2. Hiring more staff. A business takes on extra staff, so wages rise sharply. Its gross profit margin is unchanged, because trading is the same, but the profit margin falls as wages eat into profit. The contrast between the two margins shows the cause is running costs, not trading, which is exactly the kind of diagnosis the ratios are for.

Try this

Q1. Sales are $\$ 40,000 $and gross profit is$ \ $16,000$ . Find the gross profit margin. [2 marks]

Cue. $\dfrac{16\,000}{40\,000} \times 100 = 40\%$ .

Q2. Sales are $\$ 60,000 $and profit for the year is$ \ $9,000$ . Find the profit margin. [2 marks]

Cue. $\dfrac{9\,000}{60\,000} \times 100 = 15\%$ .

Q3. Explain why the profit margin is always lower than the gross profit margin. [2 marks]

Cue. The profit margin deducts all running expenses as well as the cost of goods, so less of each sales dollar is left than at the gross-profit stage.

Exam-style practice questions

Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Original6 marksA business has sales of

\

50\,000

, gross profit of

20\,000

and profit for the year of

\

8\,000$. (a) Calculate the gross profit margin and the profit margin. (b) State what each tells the owner.

Show worked answer →

(a) Gross profit margin $= \dfrac{\text{gross profit}}{\text{sales}} \times 100 = \dfrac{20\,000}{50\,000} \times 100 = 40\%$ .

Profit margin $= \dfrac{\text{profit for the year}}{\text{sales}} \times 100 = \dfrac{8\,000}{50\,000} \times 100 = 16\%$ .

(b) The $40\%$ gross profit margin means the business keeps $\$ 0.40 $of every sales dollar after the cost of the goods. The$ 16% $profit margin means$ \ $0.16$ of every sales dollar is left as profit after all expenses.

What markers reward: both ratios with their formulae, the correct percentages, and an interpretation of each in plain terms (cents kept per dollar of sales).

Original5 marksA shop's gross profit margin stayed at

35\%

but its profit margin fell from

12\%

7\%

. Suggest one reason and explain what the steady gross profit margin tells you.

Show worked answer →

If the gross profit margin is unchanged but the profit margin has fallen, the problem is not in trading (the selling price and cost of goods are in the same proportion) but in the expenses below gross profit.

One reason: the expenses, such as wages, rent or electricity, have risen, taking a bigger bite out of the gross profit and leaving less as profit for the year.

The steady gross profit margin is significant because it shows trading is unchanged, so the fall in profit must come from higher running costs, not from pricing or the cost of goods.

What markers reward: identifying that the issue lies in expenses below gross profit, one valid reason (rising expenses), and explaining that the stable gross margin rules out a trading cause.