Business studies
Contribution margin and break-even chart
Enter the price, the variable cost per unit, fixed costs and units sold: get the contribution margin, the break-even point, the margin of safety and the operating leverage, with the break-even chart.
Contribution margin and break-even point
The contribution margin is what is left of each sale after paying its variable costs: price minus variable cost per unit. It contributes first to covering fixed costs, then to profit. With a price of 50 and a variable cost of 30, each unit contributes 20.
The break-even point is the volume at which margins exactly cover fixed costs: fixed costs ÷ unit margin. With 40,000 of fixed costs, 2,000 units are needed; selling 3,000 gives a profit of 20,000 and a margin of safety of a third of sales.
Operating leverage measures how strongly profit reacts to sales: total margin ÷ operating income. In the example it is 3, so a 10% rise in sales lifts profit by 30%, and a fall cuts it just as fast. More fixed costs mean more leverage and more risk.
Common mistakes
- Counting as variable costs that do not change with volume, such as rent: the margin comes out too low.
- Confusing contribution margin with profit: the first ignores fixed costs.
- Setting the price from the break-even point alone, ignoring the market: the volume sold also depends on the price.
Frequently asked questions
How does contribution margin differ from gross margin?
Gross margin subtracts the cost of goods sold, which can include fixed production costs; contribution margin subtracts only variable costs, and it is the one needed for the break-even point.
What is the margin of safety for?
It tells how far sales can fall before a loss. A 33% margin means sales can drop by a third before reaching break-even.
How do I decide which product to push?
When a resource is scarce, such as machine hours, favour the product with the highest contribution margin per unit of that resource, not the one with the highest margin per unit.
How this calculation works
Unit margin = price − variable cost per unit; margin ratio = unit margin ÷ price. Total margin = unit margin × units; operating income = total margin − fixed costs. Break-even units = fixed costs ÷ unit margin; break-even revenue = break-even units × price. Margin of safety = (units − break-even) ÷ units. Operating leverage = total margin ÷ operating income. Units for profit P = (fixed costs + P) ÷ unit margin.
Related calculators
Break-even point
Units and turnover needed to cover fixed costs, with contribution margin and margin of safety.
Economic order quantity
The order size that minimises costs (Wilson formula), orders per year, costs and reorder point.
Markup and margin
Selling price from cost and markup or margin, with both figures.