What is the break-even point
The break-even point is the revenue at which the operation stops losing money without yet making a profit: the one where the sum of the period's contribution margins pays exactly its fixed expenses.
It is not a target you pick. It is the consequence of three numbers that were already decided beforehand: how much the overhead costs per month, how much is left of each sale after cost and variable expenses, and the mix the store sells. Changing any of the three moves the point — a promotion included.
Below it, every day of operation burns cash even with a full store. Above it, every real sold carries its slice of the contribution index straight into the result, because the month's overhead is already paid.
How the break-even point is calculated
One division — and the denominator is the contribution margin index, not gross margin. Swapping one for the other is what returns a break-even point that is comfortable and false.
break-even point in R$ = fixed expenses ÷ contribution margin index
break-even point in units = fixed expenses ÷ unit contribution margin
margin of safety = (revenue − break-even point) ÷ revenue
The allocation of fixed expenses is the same number on both sides of the calculation: in the markup calculator it enters as a percentage of the price and returns the index that makes each sale carry its slice of the overhead.
An operation with R$ 96,000 in fixed expenses per month
The calculation has two steps: first the point, which comes from the division, and then what the month's revenue leaves above it. The contribution index is the average of the mix sold — of every R$ 100.00 that comes in, R$ 32.00 is left after the cost of goods and the expenses that were born with the sale.
| Fixed expenses for the monthrent, payroll, electricity, accountant and systems | R$ 96,000 |
|---|---|
| Contribution margin indexaverage of the mix actually sold | 32% |
| Break-even point | R$ 300,000 |
| Revenue for the month | R$ 360,000 |
| Margin of safetyhow far sales can fall before a loss | 16.7% |
| Result for the month5.3% of revenue | R$ 19,200 |
Now take two points off the index — from 32% to 30%, which a month of poorly calibrated promotions does all by itself. The break-even point rises from R$ 300,000 to R$ 320,000 and the same R$ 360,000 of revenue returns R$ 12,000 instead of R$ 19,200. Thirty-seven and a half percent of the month's profit, in two index points that nobody felt at the moment of approving the promotion.
The break-even point changes all the time
It tends to be calculated once and quoted all year. Of the formula's three inputs, two change every month.
The first is fixed expense. It is fixed in relation to the volume sold, not in relation to the calendar: a rent adjustment, a hire, a new software subscription and the thirteenth-month salary shift the point without warning. A break-even point calculated in January describes an overhead that no longer exists in July.
The second is the contribution index, and it depends on the mix. Selling the same revenue with a larger share of low-index items drags down the average and raises the point, even though no price was touched. That is why two stores with the same revenue and the same overhead close the month in opposite ways: what separates the two is what each one sold, not how much.
The formula also comes in versions, and they answer different questions. The accounting break-even point is the one from the division above. The financial one subtracts from fixed expenses what is not a cash outlay in the period, such as depreciation, and answers at what revenue the cash stops shrinking. The economic one adds to fixed expenses the minimum expected return on the capital invested, and answers from when the business pays the cost of existing instead of merely sustaining itself.
None of the three versions is useful without a margin of safety. Operating 2% above the point means one bad week, a transport strike or a new competitor puts the month in the red. The margin of safety is the distance between revenue and the point, and it is what says whether the operation has room to negotiate price — or whether every discount approved is being taken out of something that does not exist yet.
Where the calculation usually breaks
The four below produce a break-even point lower than the true one, which is the mistake that does not hurt right away.
Dividing fixed expense by gross margin
Gross margin deducts only the cost of goods; the contribution margin index also deducts the tax on the sale, the commission, the payment processing fee and the delivery freight. Using the first in the denominator inflates the divisor and returns a break-even point well below the real one — the store believes it is in the black weeks before it is.
Classifying commission as a fixed expense
What varies with the sale does not belong in the numerator. Commission, card terminal fees and delivery freight rise when you sell more, and putting them among the fixed expenses makes the calculation demand from the operation a revenue that already pays those expenses by itself. The test is direct: if the amount falls when sales fall, it is variable.
Calculating with the list-price index, not the one actually realized
The index that matters is the one for what was sold, with the discount that was given, in the mix that went out. A month with 15% of the volume on promotion has an average index below that of the price list, and it is that lower index that defines the point. Calculating from the price list means describing a store that sold something else.
Treating the number as annual
Revenue has seasonality and fixed expense has a calendar. December and February look nothing alike, and an annual average break-even point describes neither: it hides the months in which the operation runs below it and overstates the slack of the strong months. The useful calculation is monthly, with that month's expenses.
The terms that decide price together with this one
No pricing term explains itself alone. These are the ones that appear in the same decision, each with its definition and its calculation.
Further reading
What the blog has already published about break-even point and about what this definition addresses.
Understanding the calculation is one thing; redoing it across thousands of items is another
For one product, any of these calculations fits in a spreadsheet. Across an entire catalog, with cost changing on every incoming invoice, it stops being done — and the price ends up inherited from the previous month.