Contribution margin — the number that matters
Break-even analysis rests on one idea: every unit you sell contributes something toward covering your fixed costs. That something is the contribution margin — the selling price minus the variable cost of producing that unit.
Break-even units = Fixed costs ÷ Contribution margin
Break-even revenue = Break-even units × Price per unit
- Fixed costs
- Costs that do not vary with volume
- Variable cost
- Cost incurred per additional unit sold
Once you have sold enough units for the accumulated contribution to equal your fixed costs, every further unit is profit. Before that point, every unit reduces your loss.
A worked example
Unit 1,251 delivers $40 of pure profit. Selling 1,500 units yields $10,000 profit.
Reaching a target profit
Treat the target as an additional fixed cost. To make $20,000 profit: (50,000 + 20,000) ÷ 40 = 1,750 units. Enter a figure in the advanced options above to see this directly.
Margin of safety
The margin of safety is how far sales can fall from expected levels before you hit break-even. It is the single most useful output of this analysis, because it measures how much room for error the business has.
If you expect 2,000 units and break even at 1,250, the margin of safety is 37.5% — sales could drop by more than a third before you lose money. Below about 20%, the business is fragile to any downturn.
Operating leverage
A business with high fixed costs and low variable costs — software, airlines, manufacturing — has high operating leverage. Break-even is far away, but every unit past it is very profitable. A business with low fixed costs and high variable costs — consulting, retail — breaks even quickly but each sale contributes less.
High leverage magnifies both directions. It is why software companies are wildly profitable at scale and catastrophic below it.
What the model assumes
- Price stays constant. In reality, selling more often requires discounting.
- Variable cost per unit stays constant. Bulk purchasing usually reduces it at volume.
- Fixed costs stay fixed. They are only fixed within a range — doubling output may need another facility.
- A single product, or a stable sales mix. With multiple products, use a weighted average contribution margin.
- Everything produced is sold. Inventory build-up is ignored.
Treat break-even as a planning benchmark rather than a forecast. Pair it with the profit margin calculator and the ROI calculator for a fuller picture.
Frequently asked questions
How do I calculate the break-even point?
Divide fixed costs by the contribution margin per unit, where contribution margin is selling price minus variable cost per unit.
With $50,000 fixed costs, a $100 price and $60 variable cost: 50,000 ÷ 40 = 1,250 units.
What is the difference between fixed and variable costs?
Fixed costs stay the same regardless of how much you sell — rent, salaried staff, insurance, software subscriptions. Variable costs are incurred per unit sold — materials, packaging, shipping, payment processing fees, sales commission.
Some costs are mixed. A phone plan with a monthly fee plus per-minute charges should be split into its fixed and variable parts.
What if I sell multiple products?
Use a weighted average contribution margin based on your expected sales mix. If 60% of units are product A with a $40 margin and 40% are product B with a $25 margin, the weighted average is $34.
This holds only while the mix does, so recalculate if the mix shifts.
What is a good margin of safety?
Above 30% is comfortable; below 20% is fragile. It means sales could fall that far before you start losing money.
Businesses with volatile or seasonal demand need a larger cushion than those with stable subscription revenue.
How do I lower my break-even point?
Three levers: raise the price, reduce variable cost per unit, or cut fixed costs. Price is usually the most powerful — a 10% price rise on the example above cuts break-even from 1,250 to 1,000 units.
Converting fixed costs to variable ones, such as outsourcing rather than hiring, also lowers break-even, though it reduces the profit at high volumes.