SingaporeAccountingSyllabus dot point

How is the break-even point calculated, and what does the margin of safety tell a business about its risk?

Calculate the break-even point and margin of safety and interpret the break-even chart

A focused answer to the H2 Principles of Accounting outcome on break-even analysis. The break-even point in units and revenue, the margin of safety, the break-even chart, and how these measure operating risk.

Generated by Claude Opus 4.810 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 the break-even point and the margin of safety, and to interpret the break-even chart. Break-even analysis answers the most basic survival question: how much must we sell to avoid a loss, and how much cushion do we have? The central insight is that break-even is the volume at which contribution exactly covers fixed costs, and the margin of safety measures how far sales can fall before that point is breached.

The answer

The break-even point

Break-even is where total contribution equals fixed costs, so profit is zero:

\text{Break-even (units)} = \frac{\text{fixed costs}}{\text{contribution per unit}}

In revenue terms, divide fixed costs by the contribution-to-sales ratio:

\text{Break-even (revenue)} = \frac{\text{fixed costs}}{\text{C/S ratio}}

Below break-even the firm makes a loss; above it, every unit's contribution becomes profit.

The margin of safety

The margin of safety is how far current or expected sales exceed break-even:

\text{Margin of safety (units)} = \text{actual or budgeted sales} - \text{break-even sales}

\text{Margin of safety (\%)} = \frac{\text{actual sales} - \text{break-even sales}}{\text{actual sales}} \times 100

A large margin means sales can fall a long way before a loss; a small margin signals vulnerability to any dip in demand.

The break-even chart

A break-even chart plots, against output:

Total revenue - a line from the origin rising at the selling price per unit.
Total cost - a line starting at the fixed-cost level on the vertical axis, rising at the variable cost per unit.

The lines cross at the break-even point. To the left, total cost exceeds revenue (a loss); to the right, revenue exceeds cost (a profit). The vertical gap between the lines is the profit or loss at any output, and the horizontal distance from break-even to expected sales is the margin of safety.

Worked example

A company sells a product for $\$ 50 $, with variable cost$ \ $30$ per unit and fixed costs $\$ 200,000 $. Budgeted sales are$ 13,000$ units. Find the break-even point, the margin of safety, and the profit at budgeted sales.

Step 1: Contribution and break-even units

Contribution per unit $= 50 - 30 = \$ 20 $. Break-even$ = \dfrac{200,000}{20} = 10,000$ units.

Step 2: Break-even revenue

C/S ratio $= \dfrac{20}{50} = 0.4$ . Break-even revenue $= \dfrac{200\,000}{0.4} = \$ 500,000 $(check:$ 10,000 \times 50$).

Step 3: Margin of safety

Units $= 13\,000 - 10\,000 = 3\,000$ . Percentage $= \dfrac{3\,000}{13\,000} \times 100 \approx 23\%$ .

Step 4: Profit at budget

\text{Profit} = (13\,000 \times 20) - 200\,000 = 260\,000 - 200\,000 = \$60\,000

The firm breaks even at $10\,000$ units and has a $23\%$ cushion before a loss, earning $\$ 60,000 $at budget. The$ 3,000 $-unit margin of safety contributes$ 3,000 \times 20 = \ $60\,000$ , exactly the profit, confirming that profit equals the margin of safety times contribution per unit.

Examples in context

Example 1. Two firms, different cost structures. A labour-intensive firm has low fixed costs and a low break-even, so it is hard to push into a loss but its profits grow slowly. A capital-intensive rival has high fixed costs and a high break-even; below it the losses are heavy, but above it profits soar. The break-even point and margin of safety reveal which firm is riskier at a given sales level, exactly the comparison the chart makes visible.

Example 2. Setting a sales floor. A manager learns the break-even is $8\,000$ units against a forecast of $9\,000$ , a margin of safety of just $1\,000$ units ( $11\%$ ). Recognising the thin cushion, the manager negotiates lower fixed costs or a higher price to push break-even down and widen the margin of safety, reducing the risk that a small demand shortfall causes a loss.

Try this

Q1. Fixed costs are $\$ 90,000 $and contribution is$ \ $15$ per unit. Find the break-even point. [2 marks]

Cue. $\dfrac{90\,000}{15} = 6\,000$ units.

Q2. Break-even is $5\,000$ units and budgeted sales are $7\,000$ units. Find the margin of safety in units and percentage. [2 marks]

Cue. Margin $= 7\,000 - 5\,000 = 2\,000$ units; percentage $= \dfrac{2\,000}{7\,000} \times 100 \approx 29\%$ .

Q3. Explain what the point where the total revenue and total cost lines cross on a break-even chart represents. [2 marks]

Cue. It is the break-even point, the output at which revenue equals total cost so profit is zero; left of it the firm makes a loss, right of it a profit.

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.

Original7 marksA firm sells a product for

\

with variable cost

36

per unit and fixed costs of

\

180\,000

. It expects to sell

10\,000$ units. (a) Calculate the break-even point in units and in revenue. (b) Calculate the margin of safety in units and as a percentage.

Show worked answer →

Contribution per unit $= 60 - 36 = \$ 24$.

(a) Break-even point (units) $= \dfrac{\text{fixed costs}}{\text{contribution per unit}} = \dfrac{180\,000}{24} = 7\,500 \text{ units}$ .

Break-even revenue $= 7\,500 \times 60 = \$ 450,000 $(or fixed costs divided by the C/S ratio: C/S$ = \dfrac{24}{60} = 0.4 $, so$ \dfrac{180,000}{0.4} = \ $450\,000$ ).

(b) Margin of safety (units) $=$ expected sales $-$ break-even $= 10\,000 - 7\,500 = 2\,500 \text{ units}$ .

Margin of safety (%) $= \dfrac{2\,500}{10\,000} \times 100 = 25\%$ .

Markers reward the $\$ 24 $contribution, break-even of$ 7,500 $units and$ \ $450\,000$ , and a margin of safety of $2\,500$ units or $25\%$ .

Original5 marksExplain what the margin of safety measures and why a business with high fixed costs and a low margin of safety is more risky.

Show worked answer →

The margin of safety is the amount by which expected (or actual) sales exceed the break-even point. It measures how far sales can fall before the business makes a loss, expressed in units, revenue or as a percentage of sales. A larger margin of safety means more cushion against a downturn.

A business with high fixed costs has a high break-even point, because a lot of contribution is needed just to cover the fixed costs. If its margin of safety is also low, sales are only just above break-even, so even a small fall in demand could push it into a loss. High operating gearing (a large fixed-cost base) magnifies the profit impact of changes in volume, so the combination of high fixed costs and a thin margin of safety is risky.

Markers reward defining the margin of safety as the gap above break-even, the point that it shows how far sales can fall, and the link between high fixed costs, a low margin and greater risk.