Find the sales volume where your business stops losing money: break-even units and revenue from fixed costs, price and variable cost — plus margin of safety, profit at your target volume, the units needed for a profit goal, and what a price change does to the break-even point. Everything updates live in your browser; the defaults are the worked example.
The maths: contribution margin = price − variable cost. Break-even units = fixed costs ÷ contribution margin, rounded up — you cannot sell two-thirds of a unit, so 666.67 becomes 667.
Break-even revenue uses the exact (unrounded) break-even volume × price — 666.67 units × $45 = $30,000 — because revenue is a money total, not a unit count. Margin of safety also uses the exact break-even volume, for the same reason. Unit counts themselves are always rounded up.
Same fixed and variable costs, only the price moves. A small price rise cuts the break-even volume sharply; a price cut pushes it up just as fast.
| Price scenario | Price | Margin / unit | Break-even units | Break-even revenue |
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Break-even units and revenue from fixed costs, price and variable cost — with contribution margin, margin of safety, target-profit units and a price sensitivity table.
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Work out the break-even point of a product or business from fixed costs, price per unit and variable cost per unit: contribution margin, break-even units and revenue, profit at your expected sales, margin of safety, the units needed for a target profit, and a sensitivity table showing what a price change does to the break-even volume.
A business has $12,000 of fixed costs, sells at $45 and spends $27 of variable cost per unit, so each sale contributes $45 − $27 = $18 toward fixed costs. Break-even is $12,000 ÷ $18 = 666.67 units, rounded up to 667 units; break-even revenue is 666.67 × $45 = $30,000 (the exact volume × price — see Method). At a target of 1,000 units, profit is 1,000 × $18 − $12,000 = $6,000 and the margin of safety is (1,000 − 666.67) ÷ 1,000 = 33.33% — sales can fall a third before losses start. For a $9,000 profit the business needs (12,000 + 9,000) ÷ $18 = 1,166.67, rounded up to 1,167 units.
Contribution margin = price per unit − variable cost per unit. Break-even units = fixed costs ÷ contribution margin, rounded up to the next whole unit (you cannot sell a fraction of a unit). Break-even revenue = the exact, unrounded break-even volume × price — a deliberate choice: revenue is a money total, so 666.67 × $45 = $30,000 exactly, rather than the rounded 667 × $45 = $30,015. Profit at a target volume = target units × contribution margin − fixed costs. Margin of safety % = (target units − exact break-even units) ÷ target units × 100, again using the exact break-even volume. Units for a target profit = (fixed costs + target profit) ÷ contribution margin, rounded up. If price is at or below variable cost, the contribution margin is zero or negative and no break-even exists — the calculator says so instead of showing a negative volume.
Price minus variable cost per unit — the amount each sale contributes toward fixed costs and then profit. At a $45 price and $27 variable cost the margin is $18: the first $12,000 of those $18 contributions pays the fixed costs (break-even), and every $18 after that is profit.
Because you cannot sell two-thirds of a unit. 666 units at an $18 margin contribute $11,988 — still $12 short of $12,000 of fixed costs — while 667 units contribute $12,006 and cross the line. Rounding down would show a “break-even” that still loses money.
Revenue is calculated from the exact break-even volume (666.67 units × $45) because it is a money total, not a unit count. The unit count is what must be rounded up to a whole unit. The $15 difference is the rounding on the 667th unit — both figures are shown with their method stated so you can reconcile them.
How far your expected sales sit above break-even, as a percentage of expected sales: (target − break-even) ÷ target. At 33.33%, sales can fall by a third before the business starts losing money. A negative margin of safety means the target itself is below break-even.
Then every sale loses money before fixed costs are even considered, and no sales volume can break even — selling more makes the loss bigger. The calculator flags this state clearly instead of showing a negative break-even; the fix is a higher price or a lower variable cost.
Yes — treat one billable unit (an hour, a project, a booking) as the unit: its price, the variable cost of delivering it (contractors, materials, per-job fees), and your fixed monthly costs. The maths is identical; only the labels change.
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