Contribution margin and break-even
“How much do I need to sell in order not to lose money?” It is perhaps the most concrete question an entrepreneur can ask, and the answer does not lie in revenue but in two concepts that many confuse or ignore: the contribution margin and the break-even point. Understanding them changes the way you think about prices, discounts and volumes. They are simple arithmetic, yet they explain why a company with high revenue can lose money and one with low revenue can earn it.
Fixed costs and variable costs
It all starts with a distinction. Variable costs change with volume: raw materials, commissions, the production cost of each individual unit. Fixed costs stay the same whether you sell one item or a thousand: rent, salaries, social security contributions, LPP (occupational pension), licences, depreciation.
This separation is the heart of everything. Without distinguishing the two types of cost, you cannot calculate either the contribution margin or the break-even point.
What the contribution margin is
The contribution margin is what remains of the selling price once variable costs are removed:
Selling price − variable costs = contribution margin
It is called “contribution” margin because it is what each sale contributes to covering fixed costs. Until fixed costs are covered, that margin serves to fill the gap; once they are covered, it becomes profit.
An example with simple numbers: if you sell a product for CHF 100 and variable costs are CHF 60, the contribution margin is CHF 40, i.e. 40%. Every item sold puts CHF 40 into the “piggy bank” that has to cover fixed costs.
Calculating the break-even point
The break-even point is the sales volume at which the total contribution margin exactly equals fixed costs: neither profit nor loss. The formula is direct:
Fixed costs ÷ unit contribution margin = break-even quantity
Returning to the example: with CHF 40 of margin per item and fixed costs of CHF 120,000 a year, break-even is at 3,000 items. Below that number you lose money, above it you earn. If you prefer to think in francs rather than units, divide fixed costs by the margin percentage (40%): break-even is at CHF 300,000 in revenue.
What it is really for
These two numbers are not a theoretical exercise. They serve to make concrete decisions:
- Prices and discounts: a discount directly reduces the contribution margin, not revenue. With a 40% margin, a 10% discount on the price burns a quarter of the margin. Knowing how many more items you have to sell to make up for it prevents discounts that seem harmless but actually erode profit.
- New products or services: an offering with a low contribution margin requires enormous volumes to pay for fixed costs. Better to know that before launching it.
- Volume decisions: knowing how far you are above or below break-even tells you how much safety margin you have before slipping into a loss.
- Investments: hiring a person or renting a larger space raises fixed costs and pushes the break-even point higher. The calculation shows how much additional revenue is needed to justify it.
The margin of safety
From the break-even point comes another useful indicator: the margin of safety, i.e. by how much current sales exceed break-even. If you sell 4,000 items and break-even is at 3,000, you have a margin of safety of 25%: sales can fall by a quarter before you enter a loss. It is a measure of how exposed you are to a slowdown — valuable information in uncertain times.
A word of caution
The model assumes that variable costs remain proportional and fixed costs stable. In reality, beyond certain volumes fixed costs make a “jump” (you need a second warehouse, an extra shift) and variable costs can fall thanks to economies of scale. Break-even is a snapshot within a reasonable range, not a law valid at every volume. It should be recalculated whenever the cost structure changes.
In summary
- Separate fixed and variable costs: it is the basis of everything.
- Contribution margin = price − variable costs.
- Break-even = fixed costs ÷ unit contribution margin.
- A discount hits the margin, not revenue: always calculate the effect.
- The margin of safety tells you how much you can lose before running a loss.
How we help you
We help SMEs calculate real contribution margins and break-even points by product and by line, and use them to decide prices, discounts and investments with the numbers in hand. We analyse your margins.