What does the contribution margin ratio mean, and how does it give my break-even revenue directly?
The contribution margin ratio is the contribution per unit divided by the price: the share of every riyal or dirham of sales left over to cover fixed costs. Divide your fixed costs by that ratio and you have break-even revenue. At a ratio of 40% with fixed costs of 10,000, break-even revenue is 25,000.
Where the ratio comes from
When you enter fixed costs, unit price and variable cost in the Break-even calculator, the top of the result shows two lines: the contribution per unit as an amount, and the contribution margin ratio as a percentage. With a price of 50 and a variable cost of 30, the contribution is 20 and the ratio is 20 ÷ 50 = 40%.
Read it this way: out of every 100 you sell, 40 goes toward rent, salaries and subscriptions, and 60 pays for the goods themselves. Once the fixed costs are covered, that 40 becomes profit.
The shortcut from fixed costs to revenue
- Take the fixed costs: 10,000.
- Divide by the ratio as a decimal: 10,000 ÷ 0.40 = 25,000.
- That is break-even revenue, shown by the calculator as 'Break-even revenue', and equal to 500 units × 50.
The shortcut lets you talk about your target in sales rather than units. If you watch daily revenue on your store dashboard, knowing the month's target is 25,000 is easier than counting units.
What happens when the ratio falls
Cut the price to 45 with the same cost. The contribution becomes 15, the ratio 33.33%, and exact break-even revenue 30,000. Five less on the price raised the sales target by 5,000. The exact unit count of 666.67 rounds up to 667, so revenue at the rounded-up units is 30,015.
That is why the calculator shows two revenue lines: 'Break-even revenue', the exact figure, and 'Revenue at the rounded-up units', which is what you will actually take because you cannot sell part of a unit. The gap is usually small, but it is there.
Where the shortcut stops working
- The ratio holds for one product at a constant price and cost. If your shop sells products with different ratios, the overall ratio moves as the sales mix moves.
- The contribution margin ratio is not profit margin. The margin in the Profit margin calculator compares price with unit cost, while this ratio tells you what is left to cover fixed costs before any profit.
- If you judge ads by return on ad spend, the ratio helps you understand an ad's break-even point in the ROAS calculator.
Common questions
Why does the calculator sometimes show the ratio as undefined?
If the selling price is zero there is nothing to divide by, so the tool shows the ratio as 'Undefined'.
Can the ratio be negative?
Yes, when the variable cost is above the price. There is then no break-even, and the tool explains why.
Do I enter the ratio myself?
No. The tool calculates it from the price and variable cost; you only use it to read the result.