Break-even analysis gives a precise number from a simple model. A strong answer does not stop at the number. It tests whether the assumptions behind the model would hold in the case and says what would change if they did not.
This lesson closes the teaching sequence in costs, revenue and break-even. It uses everything before it: classified costs, contribution, the chart and the margin of safety.
Which assumptions sit behind the number?
The standard model assumes:
- Price is constant. Discounts or price cuts change contribution.
- Variable cost per unit is constant. Bulk discounts or higher ingredient prices break this.
- Fixed costs stay fixed across the output range. A second shift or larger premises may add to them.
- Everything made is sold. Unsold stock has cost but no revenue.
- One product, or a fixed mix. Several products with different contributions need more work.
To test an assumption, change one figure at a time and recalculate break-even output. That is called a sensitivity check. Then compare the new break-even output with the planned sales.
Worked example
Warung Mee Rebus Pak Din in Kota Kinabalu plans to sell each bowl for RM6.00. Variable cost is RM3.50 a bowl. Rent and wages are RM3,000 a month.
Pak Din expects to sell 1,500 bowls a month.
Step 1, base case. Contribution = 6.00 − 3.50 = RM2.50. Break-even = 3,000 ÷ 2.50 = 1,200 bowls. Margin of safety = 1,500 − 1,200 = 300 bowls, which is 20% of planned sales.
Step 2, test three changes, one at a time.
| Change | New contribution (RM) | New fixed cost (RM) | Break-even (bowls) | Margin at 1,500 bowls |
|---|---|---|---|---|
| Base case | 2.50 | 3,000 | 1,200 | 300 |
| Price cut to RM5.50 | 2.00 | 3,000 | 1,500 | 0 |
| Variable cost up 10% to RM3.85 | 2.15 | 3,000 | 1,395.35, so 1,396 | 104 |
| Rent and wages up to RM3,600 | 2.50 | 3,600 | 1,440 | 60 |
Check the middle row: 6.00 − 3.85 = 2.15, and 3,000 ÷ 2.15 = 1,395.35. Check the price row: 3,000 ÷ 2.00 = 1,500.
Step 3, write the conclusion. “At RM6.00 the stall breaks even at 1,200 bowls, a margin of 20% of the planned 1,500. But a price cut to RM5.50 would remove the whole margin, and a 10% rise in ingredient cost would leave only 104 bowls. The stall should check how sure it is of 1,500 bowls and avoid discounting before it knows demand.”
Each sentence uses a figure from the table.
The mistake to watch for
Two slips are common. The first is to treat the base-case figure as certain.
Mistaken conclusion: Break-even is 1,200 bowls and the stall expects 1,500, so it will make a profit.
The student gave no test of the assumptions and no reasoning about how reliable 1,500 is.
The second is rounding down. 1,395.35 rounded to 1,395 leaves the fixed costs slightly uncovered.
Check: 1,395 × 2.15 = RM2,999.25, which is below RM3,000. Round up to 1,396 (1,396 × 2.15 = RM3,001.40). The correction for both is to test the figure, name the assumption, and give a conditional conclusion.
Check yourself
Try these on paper, then open each answer.
1. Fixed costs are RM3,000 and contribution per unit is RM2.40. Calculate break-even output.
Show answer
3,000 ÷ 2.40 = 1,250 units. Check: 1,250 × 2.40 = RM3,000.
2. Fixed costs are RM5,000 and contribution per unit is RM3. Calculate break-even output as a whole number of units.
Show answer
5,000 ÷ 3 = 1,666.67, so round up to 1,667 units. Check: 1,666 × 3 = RM4,998, which is not enough, and 1,667 × 3 = RM5,001, which covers the costs.
3. A restaurant buys ingredients in bulk, so variable cost per portion falls when output is high. Which assumption of the break-even model does this break, and what is the effect?
Show answer
It breaks the assumption that variable cost per unit is constant. At high output the contribution per unit would be higher than the model uses, so the real break-even output would be lower than the model says, if the discount applies to all units.
Where this leads next
Put the whole topic to work in the costs, revenue and break-even practice set, where mixed questions ask you to choose the right method. The break-even and contribution explorer lets you test a change to price or cost yourself, and the cash versus profit bridge shows why a firm can pass break-even and still run short of cash.
If you want someone to read your evaluation paragraphs against the case figures, that is a natural focus for online one-to-one Business tuition.
Please check the Cambridge pages for Business 0264 and Business Studies 0450 to see how your exam year words break-even and evaluation questions.